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Display Method:
, Available online ,
doi: 10.11884/HPLPB202537.250159
Abstract:
Relativistic magnetrons (RMs) are promising high-power microwave (HPM) sources due to their high efficiency, low operating magnetic field, and compact configuration. Miniaturization and lightweight design are critical for expanding their application scope. However, the structural dimensions of traditional microwave sources, particularly those operating in low-frequency bands, are constrained by the correlation between wavelength and radial size. As a result, the radial size of their slow-wave structures often needs to be of the same magnitude as the working wavelength, which seriously limits their miniaturization and compact design. To address this issue, a C-band RM with all-cavity extraction based on metamaterials (MTMs) is proposed in this paper. This design aims to overcome the traditional design limitations, enabling effective reduction in device radial size and weight. Particle-in-cell (PIC) simulations are conducted using CST Studio Suite to verify the performance of the MTM-based RM. For comparison, a traditional RM with identical key operating parameters such as voltage, magnetic field, internal anode radius, and frequency is simulated to validate the impact of MTMs on reducing the anode outer radius. In addition, preliminary designs of the permanent magnets for both structures are carried out using the magnetic field simulation software. Simulation results show that under an input voltage of 675 kV and a magnetic field of 0.29 T, the designed MTM-based RM generates a TEM-mode output with a power of 1.42 GW at a frequency of 4.3 GHz, corresponding to an efficiency of 52.6%. Compared with the traditional RM, when the operating performance metrics are nearly the same, the external anode radius is reduced by 5.5 mm, representing a 12% reduction in size, and the weight of the permanent magnet is reduced by 22.8%. These results demonstrate that the integration of MTMs effectively reduces the radial size of the C-band RM and the weight of the corresponding permanent magnet, which highlights the significant potential of MTMs in miniaturizing low-frequency HPM sources and provides a viable pathway for the development of lightweight, compact, and practical HPM systems.
Relativistic magnetrons (RMs) are promising high-power microwave (HPM) sources due to their high efficiency, low operating magnetic field, and compact configuration. Miniaturization and lightweight design are critical for expanding their application scope. However, the structural dimensions of traditional microwave sources, particularly those operating in low-frequency bands, are constrained by the correlation between wavelength and radial size. As a result, the radial size of their slow-wave structures often needs to be of the same magnitude as the working wavelength, which seriously limits their miniaturization and compact design. To address this issue, a C-band RM with all-cavity extraction based on metamaterials (MTMs) is proposed in this paper. This design aims to overcome the traditional design limitations, enabling effective reduction in device radial size and weight. Particle-in-cell (PIC) simulations are conducted using CST Studio Suite to verify the performance of the MTM-based RM. For comparison, a traditional RM with identical key operating parameters such as voltage, magnetic field, internal anode radius, and frequency is simulated to validate the impact of MTMs on reducing the anode outer radius. In addition, preliminary designs of the permanent magnets for both structures are carried out using the magnetic field simulation software. Simulation results show that under an input voltage of 675 kV and a magnetic field of 0.29 T, the designed MTM-based RM generates a TEM-mode output with a power of 1.42 GW at a frequency of 4.3 GHz, corresponding to an efficiency of 52.6%. Compared with the traditional RM, when the operating performance metrics are nearly the same, the external anode radius is reduced by 5.5 mm, representing a 12% reduction in size, and the weight of the permanent magnet is reduced by 22.8%. These results demonstrate that the integration of MTMs effectively reduces the radial size of the C-band RM and the weight of the corresponding permanent magnet, which highlights the significant potential of MTMs in miniaturizing low-frequency HPM sources and provides a viable pathway for the development of lightweight, compact, and practical HPM systems.
, Available online ,
doi: 10.11884/HPLPB202537.250172
Abstract:
Background Purpose Methods Results Conclusions
As the working power of Hall thrusters increases, the overall temperature of the thrusters will rise accordingly. A significant increase in temperature can lead to a decline in work performance and structural failure of the thruster. Therefore, a reasonable thermal design can significantly enhance the performance stability and reliability of Hall thrusters.
The purpose of this paper is to provide engineering guidance for the reasonable thermal design of a 12.5 kW Hall thruster without the cooling plate. In addition, a thermal model of the thruster is established and verified for the continuous optimization of the thruster’s structure.
The heat loss distribution of the 12.5 kW Hall thruster is calculated by theoretical analysis, then FEM (finite element method) is used to bulid the thermal model of a 12.5 kW Hall thruster, and six different thermal design methods are proposed in this paper. In addition, the effectiveness of different thermal design method is analyzed by finite element simulation combined with a thermal balance experiment.
The results show that the average temperature rise of each thruster part reaches 50~150 ℃ after the cooling plate is removed. Therefore, considering the main heat transfer path of thruster, six thermal design methods are proposed and simulated, respectively. The results indicate that the method 4 and the method 6, namely, intercept the radiation heat exchange between the hollow cathode and the inner coil, and increasing the emission coefficient of outer magnetic screen and the outer coil sleeve. Meanwhile, Based on the method 1, that is, blocking the heat conduction between the inner coil and the magnetic base, then a thickness of 5 mm heat insulation pad is added between the inner coil and the magnetic base. The test results show that the comparison errors between the simulations and the measurements of each component are less than 10%, and the comparison error between the magnetic base and the thruster base is the largest, which is caused by the top-down axial heat conduction in the test.
Axial heat conduction and radial heat radiation are the main heat transfer methods of the Hall thruster. According to the research results, the combination of the method 4 and 6 is the most effective way for thermal design optimization. Subsequently, the process wull be verified to achieve the purpose of significantly reducing the temperature of the thruster.
, Available online ,
doi: 10.11884/HPLPB202537.250108
Abstract:
Background Purpose Methods Results Conclusions
Aluminum, as a critical constituent material for missile casings, undergoes ablation phase transformation under X-ray irradiation, resulting in structural damage to the surface layer of the missile casing.
The aim of this research is to deeply explore the interaction between X-rays and aluminum materials, observe the key physical phenomena during the process, and understand the mechanism of the thermal effect of X-ray irradiation on aluminum foil.
Through multi-scale modeling simulation, while considering the temperature changes of both the electronic system and the lattice system, the TTM-MD model was selected to conduct thermal effect simulation of X-ray interaction with the material. The temperature of the surface electrons of the material was used to characterize the energy of the incident X-rays, in order to simulate the rapid temperature rise process of electrons when X-rays act on the surface of aluminum foil. In-depth research was conducted on the energy deposition of X-rays on the aluminum foil and the heat conduction process within the material.
By analyzing the specific influence of X-ray energy on the thermal effect of aluminum foil, the evolution laws of physical parameters such as electron and lattice temperatures, and material density over time were obtained. At the same time, the influence laws of X-ray irradiation on the thermal effect of aluminum foil were also explored: During the X-ray irradiation of the aluminum foil, the energy of the X-rays is absorbed by the aluminum foil material and converted into thermal energy. This heating effect leads to a decrease in the surface density of the aluminum foil and its gradual deposition towards the deeper layers. At the same time, the temperature increase caused by the irradiation also results in a dynamic response of the internal pressure of the aluminum foil, which first increases sharply and then gradually stabilizes. The changes in these physical parameters are not only closely related to the irradiation conditions but are also influenced by the inherent properties of the aluminum foil material.
Through multi-scale modeling and simulation studies, this paper analyzed the specific influence of X-ray energy on the thermal effect of aluminum foil, and obtained the evolution laws of physical parameters such as electron and lattice temperatures, and material density over time. The multi-scale simulation method successfully captured the characteristics of these changes, providing a perspective for understanding the thermal effect of aluminum foil under X-ray irradiation.
Effects of electromagnetic pulse and single event effect on electrical characteristics of SOI MOSFET
, Available online ,
doi: 10.11884/HPLPB202537.250047
Abstract:
Background Purpose Methods Results Conclusions
In space environments, electronic systems are vulnerable to various adverse effects, including electromagnetic pulses (EMP) and particle radiation, which can significantly degrade device performance and reliability. Silicon-On-Insulator (SOI) MOSFETs are widely used in aerospace applications due to their excellent electrical characteristics, but their response to combined radiation effects needs further investigation.
This study aims to analyze the effects of electromagnetic pulses and heavy-ion induced single-particle events on the electrical characteristics of short-channel SOI MOSFETs. It also explores the synergistic impact when both effects occur simultaneously, providing insights for improving device robustness in harsh space conditions.
A two-dimensional TCAD-based numerical model of short-channel SOI MOSFETs was developed, incorporating impact ionization, carrier generation and recombination, heat transfer, and thermodynamic effects. Electromagnetic pulses were modeled as transient voltage pulses with varying amplitudes, while heavy-ion effects were simulated through charge deposition profiles characterized by LET parameters. The influence of gate voltage, channel length, and LET on device behavior was systematically studied.
Simulation results indicate that EMP-induced voltage transients can cause avalanche breakdown in the drain PN junction, with breakdown voltage decreasing as gate bias increases or channel length shortens. The internal electric field, current density, and device temperature intensify during breakdown. Heavy-ion irradiation generates electron-hole pairs, causing transient increases in drain current, which lower the avalanche breakdown threshold when combined with EMP. Higher LET values further exacerbate device degradation by increasing ionization effects and reducing breakdown voltages. The combined effects produce more severe electrical deterioration compared to single effects.
The research demonstrates that both EMP and heavy-ion irradiation can markedly weaken the electrical stability of short-channel SOI MOSFETs. These findings underscore the importance of designing radiation-hardened devices for space applications. The study provides a theoretical basis for future investigations into the synergistic effects of radiation phenomena on power semiconductor devices.
, Available online ,
doi: 10.11884/HPLPB202537.250024
Abstract:
Background Purpose Methods Results Conclusions
High-repetition-rate electron accelerators face beam instabilities induced by wake fields from beam-vacuum chamber interactions. Geometric discontinuities at ubiquitous Con Flat (CF) knife-edge flange connections are a dominant source of beam-induced impedance in all-metal vacuum chambers.
To mitigate this impedance, this paper designs an RF-shielded flange-gasket connection structure achieving a smooth post-tightening transition at the interface, thereby minimizing impedance.
1. Electromagnetic Simulation: 3D simulations (CST) analyzed impedance effects of radial step heights and axial gaps at the transition, establishing allowable parameter ranges. 2. Deformation Simulation: ANSYS simulations modeled the shielded flange-copper gasket assembly to preliminarily determine inner diameter specifications for various gasket models. 3. Vacuum Sealing Tests: Verified ultra-high vacuum integrity under applied tightening torque. 4. Transition Geometry Testing: Measured the achieved radial step and axial gap post-tightening to define optimal copper gasket dimensions and tightening torque. 5. Comparative Simulation: CST simulations compared power loss and impedance for smooth chambers, standard flange-gasket transitions, and the proposed shielded transition.
1. Electromagnetic simulations defined critical tolerance ranges for radial step and axial gap. 2. Deformation simulations provided initial gasket inner diameter specifications. 3. Vacuum tests confirmed effective sealing at a tightening torque≥6 N·m. 4. Transition testing established the optimal tightening torque and key copper gasket dimensions ensuring minimal geometric discontinuity. 5. Comparative simulations demonstrated that the RF-shielded flange-gasket transition significantly reduces power loss and impedance compared to a standard CF transition, achieving performance close to that of a smooth vacuum chamber.
The designed RF-shielded flange-gasket connection structure effectively minimizes geometric discontinuity at the joint. Through combined electromagnetic, mechanical, and vacuum testing, critical parameters (radial step, axial gap, gasket dimensions, tightening torque≥6 N · m) were optimized. Electromagnetic verification confirms this design provides effective impedance shielding, offering a solution to mitigate wake-field-induced instabilities at flange connections in high-energy accelerators.
, Available online ,
doi: 10.11884/HPLPB202537.250051
Abstract:
Background Purpose Methods Results Conclusions
Single-phase AC-input low-ripple DC regulated power supplies are critical for sensitive applications. However, conventional designs often suffer from complex power circuit configurations, increasing cost and size while potentially compromising reliability. Achieving simultaneously low output voltage ripple, high steady-state accuracy, and wide output voltage adjustability remains a significant challenge in power electronics.
This study aims to overcome the limitations of existing topologies by proposing a novel single-phase AC-input low-ripple adjustable DC regulated power supply circuit. Furthermore, it develops a dedicated advanced control strategy to meet stringent low-ripple and high-stability performance requirements.
The fundamental principles of the proposed topology were analyzed, and its mathematical model established to characterize voltage transmission. A composite control scheme integrating reference output voltage amplitude self-compensation using improved Iterative Learning Control (ILC), and a dual-loop Proportional Complex Integral (PCI) control structure, was designed for precise low-ripple regulation and stability. Effectiveness was validated via simulation and experimental testing on a prototype.
Validation confirmed successful operation. Comparative analysis demonstrated the topology's advantages: simpler/compact structure, wide adjustable output voltage, significantly reduced ripple, and improved steady-state accuracy. The control strategy effectively ensured stability and met performance targets.
The combined novel topology and advanced control provide a viable solution for high-quality single-phase AC-input adjustable DC supplies.
, Available online ,
doi: 10.11884/HPLPB202537.250055
Abstract:
Background Purpose Methods Results Conclusions
With the increasing requirement of beam stability in particle accelerators, the accuracy of engineering control network is required to be higher.
This study aims to elaborate the specific observation scheme for large-scale tunnel control network, and introduce the control network layout, measurement mode and data processing.
In this paper, taking the booster of High Energy Photon Source (HEPS) with the circumference of 454 m as an example, aiming at the disadvantages of narrow space in the tunnel, the control network layout scheme and measurement method based on laser tracker precision measurement are proposed. At the same time, in the face of the problem of data validity detection of multiple stations and close points in the measurement process, the quality control method of adjacent single station fitting and multi-station fitting is proposed, and the point fitting error RMS is better than 0.1 mm.
Finally, the absolute point error RMS of radial, tangential and elevation coordinate components of the control network reaches 0.2 mm, which meets the installation accuracy requirements of the equipment. At the same time, in order to monitor the stability of the enhancer after the initial construction, two phases of the enhancer control network were observed in one year. The measurement results show that the deformation of the booster tunnel is about 10 mm in one year. The specific manifestation is that the tunnel foundation expands outward in the three areas of southeast, northwest and southwest.
Overall, the point accuracy of the three directions of the control network is different. The correctness and reliability of the results of the control network can be ensured through multiple control network measurements and data processing and analysis, which provides a reference for other synchrotron radiation light source.
, Available online ,
doi: 10.11884/HPLPB202537.250106
Abstract:
Background Purpose Methods Results Conclusions
In the Hard X-ray Free Electron Laser (SHINE), the normal-conducting L-band buncher plays a critical role in the compression of electron bunches, significantly improving beam quality meeting the stringent injection requirements of low emittance and low energy spread.
Due to its 2-cell structure, a dedicated digital low-level RF control system was developed.
This system, based on an architecture comprising FPGA and RF front-end boards, and adopts I/Q demodulation techniques. It incorporates amplitude and phase feedback, frequency tuning, and multi-motor coordinated for field flatness control.
During 10 kW continuous-wave (CW) operation the amplitude stability (peak-to-peak) improved from ±0.17% in open-loop to within ±0.03% under closed-loop, while the phase stability (peak-to-peak) was controlled within ±0.05°, and field flatness was maintained within ±2%, fully meeting design specifications. Additionally, a radio-frequency (RF) power calibration method based on ADC acquisition of LLRF was proposed.
Experimental results showed calibration error within ±2% when compared with power meter, demonstrating this method’s reliability as an alternative solution for RF power calibration.
, Available online ,
doi: 10.11884/HPLPB202537.250022
Abstract:
Background Purpose Methods Results Conclusions
Free electron lasers have emerged as significant advanced light sources owing to their unique advantages, including high power, excellent coherence, and wavelength tunability. Given that the peak and average brightness of an FEL depend on the quality of the electron beam generated by its injector, the optimization of the beam injector constitutes a key technical challenge in FEL development. The Hefei Infrared Free Electron Laser facility, a state-of-the-art, oscillator-type user facility providing continuously tunable mid-to-far-infrared radiation.
The injector structure of Hefei Infrared Free Electron Laser is optimized to obtain electron beams with lower emittance, shorter beam length, smaller energy spread and higher peak current intensity, so as to improve the performance of driving infrared free electron laser light source.
The optimization research is carried out by combining beam dynamics simulation with numerical simulation. Based on the previous optimization of the electron gun’s grid structure, the improved design is carried out. A new 12th sub-harmonic buncher is added to the front stage of the existing 6th sub-harmonic buncher, and then the beam is bunched and accelerated by using the appropriate traveling-wave buncher. Key parameters including the beam injection phase and the phase velocity variation in the traveling-wave buncher’s tapered section are systematically scanned to achieve 100% bunch capture efficiency and accelerate the electron beam to near-light-speed energy during the bunching stage.
Finally, the beam energy is increased to 64 MeV, and the root mean square length of the whole bunch reaches 8.5 ps. The high-energy scattered electrons are filtered out, and the electron beams scattered by ±1% bunch energy are counted. The optimized beam core achieves a root-mean-square longitudinal bunch length of 3.1 ps with an energy spread below 0.23 MeV, while the normalized transverse emittance is reduced to 9.8 mm·mrad. At the same time, the peak current intensity reaches 270 A, which is 2.7 times that of the original optimization results.
The simulation shows that the longitudinal length, energy dispersion and emittance of the core region of the bunch are significantly reduced after optimization, and the peak current intensity is greatly improved. Compared with the original structure, this scheme has significant advantages in the key performance of free electron laser, which has important engineering value for light source upgrading. The optimization method can be extended to the design of other light source injectors.
, Available online ,
doi: 10.11884/HPLPB202537.250151
Abstract:
Background Purpose Methods Results Conclusions
In the design process of microwave absorbing structures, due to the larger wavelength of low-frequency electromagnetic waves, the thickness of the corresponding absorbing body will also increase. Therefore, achieving low-frequency broadband absorption in the microwave band with a thin thickness is a challenge.
To address the technical bottleneck of limited bandwidth in thin microwave absorbing materials at low frequenciesthis study proposes a new absorbing body design scheme based on a double-layer magnetic medium and mortise structure, focusing on breaking through the constraint relationship between material thickness and absorption bandwidth to achieve efficient absorption of electromagnetic waves in the L/S frequency bands.
The metamaterial is constructed with a double-layer structure using magnetic material, combined with surface periodically arranged mortise-type metal resonant units, and utilizes the synergistic effect of magnetic loss and structural resonance to enhance electromagnetic energy dissipation.
Simulation results show that within the working frequency band, there are two absorption peaks at f1=1.36 GHz and f2=2.29 GHz, and the absorption rate exceeds 90% in the 1.16-2.82 GHz frequency band, effectively covering the L band and extending to part of the S band. Under thin-layer conditions, it achieves a wideband absorption of 1.66 GHz, resolving the inherent contradiction between thickness and bandwidth of low-frequency absorbing materials.
The novel metamaterial absorber based on double magnetic media and mortise structure can provide a feasible solution for the engineering application of the next-generation thin broadband absorbing bodies.
, Available online ,
doi: 10.11884/HPLPB202537.250107
Abstract:
Background Purpose Methods Results Conclusions
The operational reliability of Unmanned Aerial Vehicles (UAVs) is critically dependent on their Global Navigation Satellite Systems (GNSS). However, in increasingly contested electromagnetic environments, the inherent weakness of GNSS signals makes them highly susceptible to suppression jamming, leading to performance degradation or mission failure. Existing test standards often focus on single-jammer, static scenarios and lack the quantitative rigor needed to assess the performance of advanced multi-element antenna systems under complex, dynamic conditions.
This research aims to address this gap by developing and validating a standardized, quantitative test methodology for evaluating the anti-suppression-jamming performance of UAV GNSS systems. The objective is to create a reproducible framework that can simulate dynamic, multi-source interference and provide a comprehensive assessment from the RF front-end to the complete system level.
A hybrid test methodology integrating direct Radio Frequency (RF) injection and over-the-air (OTA) spatial irradiation was established within a microwave anechoic chamber. This “injection-irradiation” approach facilitates a full-link evaluation. Both static and dynamic tests were conducted on a seven-element GNSS adaptive array receiver. Static tests involved assessing performance against an increasing number of jammers (one to six) from fixed spatial locations. Dynamic tests simulated UAV maneuvers by placing the receiver on a turntable rotating at 2°/s, exposing it to a changing interference geometry. Performance was quantified by the jamming-to-signal (J/S) ratio threshold, carrier-to-noise ratio, and positioning success rate.
Static tests quantified a distinct saturation effect on the receiver’s spatial filtering capability; the J/S ratio threshold for positioning failure decreased from 106 dB against a single continuous-wave jammer to 60 dB against six broadband noise jammers. Critically, dynamic tests revealed a complex spatio-temporal coupling effect. In the six-jammer scenario, the system maintained a 100% positioning success rate at a J/S ratio of 70 dB while rotating, paradoxically outperforming its 60 dB static failure threshold. This demonstrates that the constant change in interference geometry can prevent the algorithm from settling into a worst-case nulling solution.
The proposed combined injection-irradiation and dynamic test methodology provides a robust and standardized framework for the quantitative assessment of UAV GNSS anti-jamming capabilities. The findings reveal that static tests alone are insufficient for predicting performance, as dynamic conditions can fundamentally alter the system’s response to multi-source interference. This research offers a critical tool for the realistic evaluation, design optimization, and validation of navigation systems intended for operation in complex electromagnetic environments.
, Available online ,
doi: 10.11884/HPLPB202537.250069
Abstract:
A trapezoidal double ridge waveguide slow wave structure has been proposed to further enhance the interaction impedance and output power of backward wave oscillators. Compared to conventional sine double ridge waveguide and flat-roofed sine double ridge waveguide, significant improvements in both the axial interaction impedance at the center of the electron beam channel and the average interaction impedance across the cross-section are observed, while maintaining a similar normalized phase velocity. Simulation results indicate that within the frequency range of 320～360 GHz, the average interaction impedance of the trapezoidal double ridge waveguide is increased by 78.33% to 86.97% compared to the sine double ridge waveguide, and by at least 46.65% compared to the flat-roofed sine double ridge waveguide. Under the same operating conditions and frequency range, the output power of the trapezoidal double ridge waveguide backward wave oscillator in the 340 GHz band is measured to be 5.55～8.03 W, representing an increase of 26.97% to 73.44% compared to the sine double ridge waveguide and an enhancement of 33.65% to 52.47% over the flat-roofed sine double ridge waveguide. At this point, all three types of backward wave oscillators are optimized for tube length, with the trapezoidal double ridge waveguide backward wave oscillator being at least 16.5% shorter than the other two structures.
A trapezoidal double ridge waveguide slow wave structure has been proposed to further enhance the interaction impedance and output power of backward wave oscillators. Compared to conventional sine double ridge waveguide and flat-roofed sine double ridge waveguide, significant improvements in both the axial interaction impedance at the center of the electron beam channel and the average interaction impedance across the cross-section are observed, while maintaining a similar normalized phase velocity. Simulation results indicate that within the frequency range of 320～360 GHz, the average interaction impedance of the trapezoidal double ridge waveguide is increased by 78.33% to 86.97% compared to the sine double ridge waveguide, and by at least 46.65% compared to the flat-roofed sine double ridge waveguide. Under the same operating conditions and frequency range, the output power of the trapezoidal double ridge waveguide backward wave oscillator in the 340 GHz band is measured to be 5.55～8.03 W, representing an increase of 26.97% to 73.44% compared to the sine double ridge waveguide and an enhancement of 33.65% to 52.47% over the flat-roofed sine double ridge waveguide. At this point, all three types of backward wave oscillators are optimized for tube length, with the trapezoidal double ridge waveguide backward wave oscillator being at least 16.5% shorter than the other two structures.
, Available online ,
doi: 10.11884/HPLPB202537.250033
Abstract:
Laser-driven high-brightness betatron radiation has great potentials for its broad applications in the detection of ultrafast processes (such as shock waves or implosion processes) in high energy density physics. Here a tube-like gas-cell target is proposed to generate a near-critical-density (NCD) plasma, which has a sharped rising edge with a length scale of hundreds of μm. Such a gas-cell target has the advantages of low back pressure and small jet volume. Moreover, due to the confinement of the gas chamber walls, it can more stably generate a plateau-shaped gas density distribution. Particle-in-cell (PIC) simulations of the the petawatt femtosecond laser interacting with such a NCD plasma were carried out to study the electron acceleration as well as the betatron radiation. It was shown that, with the appropriate gas density and pulse duration, a steady plasma channel can be well formed. In the channel, the electrons firstly undergo the wakefield acceleration. Then these energetic electrons directly interact with the laser tail, where the efficient betatron resonance and the direct laser acceleration happen, thus resulting in the great enhancement of both the yield and cut-off energy. The transverse oscillation of energetic electrons in the plasma channel leads to the production of high brightness betatron radiation, which has a critical photon energy of 8keV and a brightness of\begin{document}$ 1.75\times {10}^{20}\;\mathrm{p}\mathrm{h}\cdot {\mathrm{s}}^{-1}\cdot {\mathrm{mm}}^{-2}\cdot {\mathrm{m}\mathrm{rad}}^{-2}\cdot {\left(0.1\mathrm{{\text{%}}}\mathrm{b}\mathrm{w}\right)}^{-1} $\end{document} ![]()
![]()
Laser-driven high-brightness betatron radiation has great potentials for its broad applications in the detection of ultrafast processes (such as shock waves or implosion processes) in high energy density physics. Here a tube-like gas-cell target is proposed to generate a near-critical-density (NCD) plasma, which has a sharped rising edge with a length scale of hundreds of μm. Such a gas-cell target has the advantages of low back pressure and small jet volume. Moreover, due to the confinement of the gas chamber walls, it can more stably generate a plateau-shaped gas density distribution. Particle-in-cell (PIC) simulations of the the petawatt femtosecond laser interacting with such a NCD plasma were carried out to study the electron acceleration as well as the betatron radiation. It was shown that, with the appropriate gas density and pulse duration, a steady plasma channel can be well formed. In the channel, the electrons firstly undergo the wakefield acceleration. Then these energetic electrons directly interact with the laser tail, where the efficient betatron resonance and the direct laser acceleration happen, thus resulting in the great enhancement of both the yield and cut-off energy. The transverse oscillation of energetic electrons in the plasma channel leads to the production of high brightness betatron radiation, which has a critical photon energy of 8keV and a brightness of
, Available online ,
doi: 10.11884/HPLPB202537.240438
Abstract:
In this paper, view factors are crucial for radiative heat transfer calculation in high-temperature pebble beds. Traditional numerical calculation of view factors demands complex integration, and different formulas are needed for various geometries, leading to high computational complexity. To address this issue, we proposed a view factors model based on ray tracing and combined with particle radiation characteristics. This model eliminates the need for discrete analysis in particle modeling; it only requires particle coordinates and radii for computation. When comparing the results of ray tracing and the numerical method for tangent particles, we found that when the optical density reaches a certain value, the relative error between the two results is within 1%. particle-particle radiation mainly concentrates along the center line, and its intensity decreases in all directions following a cosine function. When we analyzed a single particle from the randomly accumulated pebble bed particles, we determined that the radiation range was mainly within twice the diameter. This was accompanied by a cumulative angular coefficient exceeding 0.98 and the number of particles is within 100. When examining the radiation range within three times the diameter of the particles, we discovered that when the cumulative angular coefficient surpassed 0.99. This paper presents a simpler method for calculating the view factor of complex pebble beds, providing technical support for analyzing the heat radiation transfer characteristics in high-temperature pebble beds.
In this paper, view factors are crucial for radiative heat transfer calculation in high-temperature pebble beds. Traditional numerical calculation of view factors demands complex integration, and different formulas are needed for various geometries, leading to high computational complexity. To address this issue, we proposed a view factors model based on ray tracing and combined with particle radiation characteristics. This model eliminates the need for discrete analysis in particle modeling; it only requires particle coordinates and radii for computation. When comparing the results of ray tracing and the numerical method for tangent particles, we found that when the optical density reaches a certain value, the relative error between the two results is within 1%. particle-particle radiation mainly concentrates along the center line, and its intensity decreases in all directions following a cosine function. When we analyzed a single particle from the randomly accumulated pebble bed particles, we determined that the radiation range was mainly within twice the diameter. This was accompanied by a cumulative angular coefficient exceeding 0.98 and the number of particles is within 100. When examining the radiation range within three times the diameter of the particles, we discovered that when the cumulative angular coefficient surpassed 0.99. This paper presents a simpler method for calculating the view factor of complex pebble beds, providing technical support for analyzing the heat radiation transfer characteristics in high-temperature pebble beds.
Articles in press have been peer-reviewed and accepted, which are not yet assigned to volumes /issues, but are citable by Digital Object Identifier (DOI).
Display Method:
, Available online ,
doi: 10.11884/HPLPB202537.250120
Abstract:
Background Purpose Methods Results Conclusions
Unmanned aerial vehicles (UAVs), representing advanced combat capabilities in new domains, have become essential weaponry in modern warfare. The proliferation of frequency-dependent equipment and rapid advancements in counter-UAV technologies have resulted in increasingly complex electromagnetic environments. High-power microwave (HPM) radiation, characterized by high power, tunable carrier frequency, and complex coupling effects, can effectively jam or damage UAV systems. Datalinks, acting as the UAV’s ‘brain’, are particularly vulnerable to HPM interference. Consequently, research into HPM coupling mechanisms and protection methods for UAV datalink is vital for enhancing UAV resilience.
This study investigates the coupling laws and protection methods of HPM radiation on the RF front-end of UAV datalinks.
Models of the datalink antenna and RF front-end PCB were developed using Computer Simulation Technology (CST) software. The antenna was irradiated with HPM pulses with variations in carrier frequency, pulse width, polarization direction, and rise time. The coupled voltage waveforms at the antenna output ports were analyzed. These voltages were injected into the receiver circuit model to determine the coupled voltage at the pins of the RF chip (Si24R1), thus simulating the complete HPM field-to-circuit coupling process. A 2.45 GHz PIN limiter was implemented for electromagnetic protection.
(1) The amplitude of the coupled voltage at the Si24R1 RF chip pins exhibited spiking behavior at high carrier frequencies. (2) Coupled voltage decreased significantly with increasing polarization angle. (3) Variations in pulse width and rise time had minimal effect on coupled voltage amplitude. (4) The PIN limiter significantly reduced the coupled voltages while maintaining signal reception quality, enhancing the datalink’s electromagnetic protection.
This work quantifies HPM coupling laws on RF front-end circuits under varying parameters. Implementing PIN limiter on the RF front-end significantly attenuates electromagnetic interference, providing a validated reference for UAV electromagnetic protection.
, Available online ,
doi: 10.11884/HPLPB202537.250152
Abstract:
Background Purpose Methods Results Conclusions
High Power Microwave (HPM) can destroy key components of communication systems through front-door coupling, resulting in system performance degradation or failure. For receivers with a single RF channel, the degree of system performance degradation can generally be evaluated using the effect results at the device level.
However, for phased array communication systems, the assessment of the system-level damage effect of HPM is a challenge. This is because there are numerous RF channels in the system, and the damage to each channel is inconsistent, making it difficult to apply the effect results at the device level to evaluate the system performance.
To verify the asymmetric damage effect of HPM on phased array communication systems and assess the impact of such asymmetric damage on system performance, this paper based on theoretical analysis, established a semi-physical simulation experiment and system-level irradiation experiment method, and conducted research on the asymmetric damage effect of typical phased array communication systems. The study investigated the additional impact of amplitude and phase inconsistency on system performance and carried out system-level verification experiments.
The results show that when the phased array communication system is damaged by HPM, asymmetric damage occurs between channels, affecting the synthesis of the phased array antenna beam, and further deteriorating the system performance.
Moreover, the greater the amplitude and phase inconsistency, especially the greater the phase inconsistency, the greater the additional loss in system performance.
, Available online ,
doi: 10.11884/HPLPB202537.250085
Abstract:
Background Purpose Methods Results Conclusions
Transient intense electromagnetic pulses, characterized by extremely high peak field strength and broad frequency domain distribution, pose severe electromagnetic safety threats to electronic systems. Their accurate measurement is crucial for evaluating radiation source performance and the effectiveness of protection measures. However, ground-reflected waves often cause significant waveform distortion in far-field measurements. Existing narrow-spectrum suppression methods fail due to bandwidth limitations, while environmental adjustment approaches are impractical in complex scenarios, and traditional array beamforming techniques are restricted by signal correlation requirements.
To address the waveform distortion caused by ground-reflected waves in far-field measurements of transient intense electromagnetic pulses, this study proposes a monopole array-based waveform recovery algorithm. It aims to eliminate ground scattering interference and accurately extract direct waves, providing support for related measurements and evaluations.
The principle of direct wave extraction based on monopole array was derived in both frequency and time domains. Potential error sources and corresponding optimization schemes were analyzed. A measurement system was built under ground reflection conditions for experimental tests, and the performance of different algorithms was compared.
Experimental results show that the direct waves extracted by the proposed algorithm match the reference direct waves well, with amplitude error within 0.2 dB and main waveform fidelity coefficient greater than 0.99. The time-domain algorithm is more concise and less affected by interference, while the frequency-domain algorithm enables direct wave recovery with a single system, making it more cost-effective. Compared with traditional technologies, the algorithm expands the applicable frequency band and significantly reduces amplitude calculation error.
The proposed waveform recovery algorithm can effectively suppress ground scattering effects and accurately extract direct waves. It provides reliable support for parameter separation in transient pulse measurements and state evaluation of radiation systems.
, Available online ,
doi: 10.11884/HPLPB202537.250009
Abstract:
Background Purpose Methods Results Conclusions
Shutdown dose rate (SDR) analysis plays a critical role in ensuring radiation safety during reactor maintenance, transportation, and decommissioning. Traditional methods such as the direct one-step (D1S) method and the rigorous two-step (R2S) method face limitations in accuracy and implementation, especially for compact and complex geometries like vehicle-mounted micro-nuclear power systems.
This study aims to develop and validate a cell-in-mesh-based R2S method for SDR calculations, with enhanced sampling efficiency and spatial resolution. The goal is to enable accurate prediction of post-shutdown radiation fields for both benchmarking and practical reactor applications.
An improved R2S methodology was implemented by integrating nested cell-in-mesh geometry with a Monte Carlo (MC) transport framework. Photon source sampling was optimized using bounding box division and local mesh-based distribution sampling. The method was validated using the ITER shutdown dose rate benchmark and applied to the Megapower microreactor model, which employs HALEU fuel, heat pipe cooling, and composite shielding.
The developed method produced SDR distributions with statistical deviations below 2% and matched international benchmark results within 4% deviation. In the Megapower case, the highest dose rate (16.3 mSv/h) at a radial location 30 cm occurred near the heat pipe outlet, primarily due to activated structural materials and neutron streaming along the heat pipe path.
The cell-in-mesh-based R2S method improves the accuracy and resolution of SDR calculations without significantly increasing computational costs. It is suitable for advanced shielding analysis of compact nuclear systems and provides a reliable tool for guiding safety design, maintenance planning, and decommissioning strategies.
, Available online ,
doi: 10.11884/HPLPB202537.250131
Abstract:
Background Purpose Methods Results Conclusions
With the increasing demand for solid-state, modular, and miniaturized pulsed power systems, wide-band-gap photoconductive semiconductor switches (PCSSs) have attracted significant attention due to their high-power capacity and fast response characteristics.
This study aims to develop a vertical PCSS on high-purity semi-insulating (HPSI) 4H-SiC substrate with an improved package structure to enhance laser energy utilization, while optimizing the pulse-forming circuit to minimize parasitic effects.
We fabricated vertical PCSSs on HPSI 4H-SiC substrates and proposed a novel package structure with a high reflector based on MgF2/TiO2 to improve laser energy utilization. And a slotted pulse-forming line structure is introduced to reduce parasitic inductance.
Under 10 kV bias voltage with 532 nm laser excitation (500 ps pulse width, 90 μJ energy), the system generated 7.6 kV pulses across 50 Ω load with 620 ps rise time and 2.2 ns pulse width. The peak output power reached 1.1 MW with 7.7 dB photoelectric power gain.
The developed SiC PCSS with high-reflector package demonstrates enhanced laser energy utilization. The slotted pulse-forming line effectively reduces parasitic inductance, enabling high-power, fast-response performance suitable for compact pulsed power systems.
, Available online ,
doi: 10.11884/HPLPB202537.250017
Abstract:
Background Purpose Methods Results Conclusions
Magnetically driven flyer plate technology can be used for the study of high-pressure equation of state and material properties. Generally, when the same force pushes objects of different masses, the lighter object always gains greater velocity. However, in a magnetically driven symmetrical flyer plate launch experiment, the same current drove two flyer plate couple of thicknesses 0.37 mm and 0.48 mm. The final measurement velocity of the 0.37 mm flyer plate couple was 18 km/s, and the final measurement velocity of 0.48 mm flyer plate couple was 19 km/s; that is, the measured velocity of the thick flyer plate couple was even greater.
This paper studies the physical mechanism of this anomalous phenomenon in the magnetically driven symmetrical flyer plate launch experiment.
A two-dimensional magnetically driven simulation code (MDSC2), in which the boundary magnetic field is affected by ablation, was used to simulate and analyze this experiment.
The numerical simulation shows that, the MDSC2 code with the boundary magnetic field affected by ablation can correctly simulate the dynamic process of 0.37 mm and 0.48 mm flyer plate couple, and the simulated velocities of 0.37 mm and 0.48 mm flyer plate couple are consistent with the measured velocities. The reason the final recorded velocity of the thicker flyer plate couple is larger than that of thinner one is that the time to complete melting for the thicker flyer plate is longer than that of thinner one in the magnetically driven symmetrical flyer plate experiment.
This work advances the physical understanding of magnetically driven flyer plate launch process, and further confirms the correctness of the boundary magnetic field formula with the ablation effect.
, Available online ,
doi: 10.11884/HPLPB202537.250097
Abstract:
Background Purpose Methods Results Conclusions
High power microwave (HPM) pulse technology has developed rapidly due to its applications in particle accelerators, radar, communications, directed energy, plasma physics, and other fields. Pulse compression technology provides an effective method for enhancing the peak power of microwave pulses.
In order to study a low-cost, miniaturized, stable, and arrayable SLAC Energy Doubler (SLED) based on vacuum electronic oscillators such as magnetrons, a high power fast bi-phase modulator with megawatt-level capacity and nanosecond response time has been designed.
Insert a conventional PIN diode loaded-line type phase-shifting circuit into the waveguide structure, and the equivalent impedance of the phase-shifting circuit changes by switching the “on” and “off” states of the PIN diodes through the waveguide external bias circuit, then the waveguide transmission microwave phase changes. The high-power characteristics of such PIN diode waveguide phase shifters have been verified by high-power experiments.
In this paper, a 180° phase shift is realized by cascading 8 phase-shifting circuit cells. The frequency-domain and time-domain parameters of the designed bi-phase modulator are tested. The frequency-domain test results show that the insertion loss of the bi-phase modulator is less than 0.7 dB, and the phase shift is 172° at the center frequency of 2.458 GHz. The error of the phase shift is within ±4° compared with that of the design value in simulation. The time-domain test results show that the inversion time of the bi-phase modulator is about 5 ns.
Compared with traditional semiconductor phase shifters, this bi-phase modulator can achieve the same phase-reversal speed while withstanding high power capacities, making it extremely valuable in the HPM field.
, Available online ,
doi: 10.11884/HPLPB202537.250043
Abstract:
Background Purpose Methods Results Conclusions
With the development of active phased array radar systems, the demand for transmit-receive (TR) power supplies has increased significantly. Modern TR modules require power supplies with wide input voltage ranges, high-frequency operation, and high efficiency. dual-active bridge (DAB) converters are widely recognized for their ability to achieve these characteristics, offering diverse control strategies and broad application potential. However, key system parameters such as inductance and switching frequency in DAB converters significantly impact power transmission capabilities and the on-state current of power MOSFETs, posing challenges for optimal design.
This study aims to address these challenges by proposing a parameter optimization design method for DAB converters based on extended phase-shift (EPS) modulation. The goal is to ensure reliable operation under overload conditions while meeting critical design constraints, including maximum power transfer, MOSFET current derating, and output voltage ripple reduction.
The power transfer characteristics and inductor current expressions of the EPS-modulated DAB converter were derived theoretically. A reliability-oriented operating region (ROA) was defined by integrating constraints such as maximum power transfer under overload, MOSFET on-state current derating, and minimum output voltage ripple frequency. The optimization process involved systematic parameter planning to determine optimal inductance values and switching frequencies.
MATLAB simulations of a dual-output DAB converter demonstrated that the proposed method effectively reduced output voltage ripple, minimized MOSFET on-state current, and achieved the desired power output. The simulation results aligned with theoretical predictions, validating the accuracy of the derived equations and the feasibility of the optimization approach.
The EPS-based parameter optimization method provides a systematic framework for designing DAB converters tailored to TR power supply requirements. By addressing key design constraints and leveraging ROA analysis, this approach enhances power transmission efficiency and device reliability. The results highlight the potential of EPS-modulated DAB converters in advanced TR modules, offering a practical solution for high-performance phased array radar systems.
, Available online ,
doi: 10.11884/HPLPB202537.250090
Abstract:
Background Purpose Methods Results Conclusions
The structure of cantilever has existed in solid surface antenna for high power microwave system. It is difficult to maintain the low acceleration for feed source structure of solid surface antenna during external vibration excitation. The traditional dynamic vibration absorber has a good control effect on the structure of cantilever. However, the application of traditional dynamic vibration absorber is limited to a narrow range of frequency.
This study aims to solve the problems of large acceleration and narrow range of frequency in traditional vibration absorber of solid surface antenna. A kind of active vibration control method combined with optimal passive absorber is proposed in this paper.
Firstly, the best installed position of dynamic absorber is obtained by analyzing and simulating the model of solid surface antenna. Secondly, the optimal parameters are calculated according to the mathematical model of simplified passive dynamic absorber system. Thirdly, the sliding mode control parameters were obtained by considering the external excitation using an active absorber method. Finally, the stability of sliding mode control method was demonstrated.
This control method combined sliding mode control with an active control absorber, which can reduce the vibration response of antenna effectively. This paper simulated the two-degree-of-freedom vibration system with active control absorber, which gave time-domain vibration response of antenna. The top point displacement of antenna under the predetermined excitation was reduced more than 95% by comparing the condition of no control strategy.
This vibration control method can effectively reduce acceleration for feed source structure, enabling it to maintain a more stable state. Furthermore, this controller can be extended to control the acceleration of various cantilever structures in pulse power equipment.
, Available online ,
doi: 10.11884/HPLPB202537.250048
Abstract:
Background Purpose Methods Results Conclusions
In modern radar and communication systems, power amplifiers determine the system's transmission output power and bandwidth, thereby affecting key performance metrics such as operating range and resolution. As operating frequencies continue to rise, the output power of a single power amplifier device is limited and cannot fully meet the current demands of radar and communication systems for broadband and high power. Therefore, it is necessary to design power synthesizer to achieve multi-channel power synthesis.
In order to achieve broadband high-power synthesis output in the microwave bands, this paper presents a novel high-power, broadband four-way rectangular waveguide TE10 mode to circular waveguide TE01 mode conversion power synthesizer.
This mode conversion power synthesizer consists of two parts, namely the structure of four rectangular waveguide TE10 mode synthesis and transformation to cross waveguide TE22 mode, and the structure of cross waveguide TE22 mode transformation to overmoded circular waveguide TE01 mode.
The simulation results show that in the Ku-band of 15.2−18.2 GHz, the synthesis efficiency of TE10-TE01 mode is greater than 99.4%, and it can withstand a maximum pulse power output of 1.6 MW. The back-to-back cold test of the experimental verification sample shows that the lowest synthesis efficiency of the power synthesizer in the frequency band of 15.2−18.2 GHz is 94%.
The simulation results and cold test show that the mode conversion power synthesizer has the characteristics of wide working bandwidth, high synthesis efficiency, and high power capacity, which can effectively solve the problem of high-power synthesis output in microwave and millimeter-wave bands.
, Available online ,
doi: 10.11884/HPLPB202537.250133
Abstract:
Background Purpose Methods Results Conclusions
Optical scattering characteristics are crucial features of space targets and play a vital role in target recognition and detection systems. Traditional methods are limited in simulating optical scattering properties -which only provide optical cross-section (OCS), scattering characteristics, or synthetic target images.
To address the above limitations and meet requirements of rendering spatial target, this paper conducts a comprehensive study on the computational modeling of optical scattering characteristics for space targets.
A systematic workflow is proposed, along with formulas for calculating target OCS, target irradiance, sky background luminance, target magnitude, signal-to-noise ratio (SNR), and detection probability. By integrating solar radiation properties, observer-site positioning, and celestial-terrestrial background sphere radiation characteristics, a graphics processing unit (GPU) accelerated framework combined with shading languages is implemented to compute time-dependent optical scattering properties, including target OCS, detector-received target/background optical power, target magnitude, SNR, detection probability, and synthetic brightness imagery.
Experimental validation using spherical and cylindrical objects confirms the accuracy of the OCS calculations. Simulations under varying observer locations, reflective properties, and detection windows demonstrate the rationality of the computed optical scattering characteristics.
This study provides a complete set of formulas, parameters, and results, offering significant value for research on space target optical scattering modeling and image-based recognition.
, Available online ,
doi: 10.11884/HPLPB202537.250041
Abstract:
Background Purpose Methods Results Conclusions
The confocal waveguide structure can effectively suppress mode competition due to its characteristic of reducing mode density through diffraction loss, thereby facilitating stable operation of gyro-traveling-wave-tube (gyro-TWT) amplifiers in the terahertz (>100 GHz) frequency range.
This study aims to conduct a comprehensive analysis of the diffraction loss rate (DLR) in a 220 GHz confocal waveguide gyro-TWT, employing a combination of theoretical analysis and three-dimensional particle-in-cell (3D-PIC) simulations.
The research integrates field distribution theory with 3D-PIC simulations to investigate the DLR of the confocal waveguide. A non-ideal waveguide model incorporating the mirror width angle was utilized, and simulations were performed to evaluate beam-wave interaction dynamics under varying DLR conditions.
The study reveals that a low DLR induces gyro-backward-wave oscillation (GBWO) in low-order competing modes, while a high DLR significantly reduces beam-wave interaction efficiency, gain, and bandwidth, and lowers tolerance to electron beam velocity spread.
For stable single-mode operation of the HE07 mode in the designed gyro-TWT, the DLR should not be less than 0.38 dB/cm, with the corresponding mirror-surface width angle not exceeding 47°. These findings provide crucial design guidelines for terahertz gyro-TWTs.
, Available online ,
doi: 10.11884/HPLPB202537.250061
Abstract:
Background Purpose Methods Results Conclusions
Tritium production pathways are well-established for large pressurized water reactors (PWRs). Integrated small reactors (ISRs), however, operate without soluble boron reactivity control and use no chemical additives (e.g., lithium hydroxide) for pH adjustment, necessitating dedicated analysis of their tritium sources.
This study aims to identify tritium production pathways in ISRs, establish a computational model for quantifying tritium source terms, and propose design optimizations to minimize tritium generation.
A theoretical model was established by solving differential equations for tritium production and removal based on identified neutron activation reaction mechanisms. Key parameters included neutron flux and nuclear cross-sections derived from Monte Carlo simulations of the ISR core. Validation was performed against normalized operational tritium release data from boiling water reactors (BWRs) with analogous B4C control rods and Sb-Be neutron sources, considering thermal power and load factors.
The annual tritium production in ISR primary coolant is 1.81 TBq. The primary contributors are neutron-activated products from Sb-Be and B4C material, accounting for 46% and 51% of the total production, respectively. Analysis of tritium discharge data from operational BWRs validates the conservatism of the theoretical results.
Optimizing secondary neutron sources (canceling Sb-Be or using double-encapsulated cladding) and replacing B4C control rods with non-tritium-producing absorbers (e.g., Ag-In-Cd or hafnium) could reduce ISR tritium production significantly. These measures are technically feasible based on PWRs operational experience and are recommended for ISR design enhancements. Future work will refine release fractions of control rods using plant-specific operational data.
, Available online ,
doi: 10.11884/HPLPB202537.250012
Abstract:
Background Purpose Methods Results Conclusions
When the primary system of nuclear reactors experiences overpressure, the overpressure discharge system can be utilized to release high-temperature and high-pressure fluid through the safety valve and downstream pipelines to achieve pressure reduction.
However, the rapid opening of the safety valve can lead to a violent fluid release, which may impose severe transient load impacts on the pipelines and the pool.
Analyzing the typical characteristics and influencing factors of the emission phenomenon can provide references for system operation and design. A systematic analysis model including the pressure vessel, pipelines, and water pool was established. The model was finely divided, with the length of the pipeline control body not exceeding 0.3 m, and the water pool was composed of multiple control bodies. The load was solved using the momentum balance method, and calculation results were compared with the EPRI/CE international test data. The established analysis model can quickly obtain the thermal response and load response during the discharge process.
The results show that during the overpressure discharge process, there is a water seal at the valve inlet and, the opening time reduction will cause the peak load on the pipelines and the water pool to increase.
A decrease in the nozzle immersion depth or an increase in the water pool cross-sectional area will result in a reduction in the peak load at the water pool.
, Available online ,
doi: 10.11884/HPLPB202537.250073
Abstract:
Background Purpose Method Result Conclusion
Radio frequency (RF) front-end components are among the most vulnerable elements in integrated circuit systems when exposed to intense electromagnetic environments. Investigating their degradation mechanisms and failure thresholds is therefore critical for identifying system weak points and devising effective protection and reinforcement strategies. However, existing high power microwave (HPM) injection tests rely on manual operation, lack standardized procedures and deliver limited repeatability.
In order to achieve precise and efficient evaluation of device degradation and failure thresholds and to establish standardized test methods and assessment procedures.
This work developed a high power microwave (HPM) automatic measurement platform grounded in the interaction mechanism between HPM and devices, and designed two testing protocols—single pulse excitation for electrical stress characterization and continuous pulse excitation for thermal failure evaluation.
A commercial low noise amplifier (LNA) served as the test device; synchronous measurements of time domain response, frequency domain characteristics and operating current, combined with pre/post test parameter comparison, pinpointed damage thresholds. Furthermore, we conducted a comprehensive evaluation of first, second, and third damage events, correlating cumulative damage effects with key device parameters through microphysical analysis to elucidate the dominant failure mechanisms.
The proposed measurement system and evaluation methodology offer a robust framework for reliability assessment of semiconductor devices in high power electromagnetic environments and provide essential experimental support for damage resilience analysis and optimized device design.
, Available online ,
doi: 10.11884/HPLPB202537.250143
Abstract:
Background Purpose Methods Results Conclusions
Precision-guided ammunition for electromagnetic railguns is gradually becoming a key area of competition among nations, which imposes new requirements on fuzes for electromagnetic railgun ammunition. Modern fuzes contain a large number of electronic components, and during the launch of electromagnetic railgun projectiles, the fuze is exposed to strong magnetic fields. These fields can interfere with the fuze's electronic components, leading to malfunctions or even damage. As a result, most mature electromagnetic railguns currently use kinetic energy projectiles or mechanical fuzes.
A reasonable arrangement of the fuze circuit module can reduce the structural thickness and weight of the electromagnetic shielding shell for the fuze circuit, while effectively ensuring the performance of the fuze circuit.
In this paper, a quasi-steady-state simulation model of the electromagnetic railgun is established. The electromagnetic induction performance of the circuit module under two different arrangement schemes is calculated and analyzed. The responses such as the magnetic field distribution, induced current, electromagnetic volume force density, and induced electromotive force on the fuze circuit module are obtained respectively.
When the fuze circuit module is arranged parallel to the projectile axis, although the overall magnetic field strength is greater than when it is arranged perpendicular to the projectile axis, the peak magnetic field strength in the perpendicular arrangement covers an entire surface of the circuit board, whereas in the parallel arrangement, the peak magnetic field strength is only at the edge of the circuit module’s end. When the fuze circuit module is arranged parallel to the projectile axis, the induced eddy current, electromagnetic volume force density, and induced electromotive force are all significantly smaller than those in the perpendicular arrangement.
For the fuze circuit module of electromagnetic railgun ammunition, arranging it parallel to the projectile axis can more effectively reduce the impact of the electromagnetic field during launch. Additionally, sensitive components should be avoided being placed at the ends and edges of the circuit module. This can greatly reduce the structural size, thickness and, weight of the shell for electromagnetic shielding of the fuze circuit components, so as to optimize the overall structure of the fuze and reduce the total weight of the fuze.
, Available online ,
doi: 10.11884/HPLPB202537.250118
Abstract:
Background Purpose Methods Results Conclusions
Unmanned aerial vehicle (UAV) data links operating in battlefield environments are highly susceptible to electromagnetic interference (EMI), frequently causing frame synchronization failures. direct sequence spread spectrum (DSSS) systems, while offering inherent interference resistance, remain vulnerable to intentional EMI attacks through front-door coupling pathways.
This study aims to establish loss-of-lock threshold models for DSSS-based UAV data links under two critical interference scenarios: in-band single-source single-tone and dual-source dual-tone EMI. The research further seeks to experimentally validate these models.
Through rigorous EMI mechanism analysis with emphasis on front-door coupling effects, the theoretical threshold models were developed for both interference scenarios. Test validation employed EMI injection testing on an operational UAV data link platform. Controlled variables included working signal power, interference frequencies, and interference power. The interference thresholds were obtained from the tests.
The test loss-of-lock thresholds demonstrated strong alignment with theoretical predictions across both interference scenarios. For single-source interference, the thresholds exhibited positive correlation with working signal power, and the absolute value of the frequency offset. Under dual-source interference, the thresholds of interference 1 showed inverse correlation with the power of interference 2.
The validated threshold models provide a theoretical foundation for EMI sensitivity assessment and test design in UAV data link systems. Key findings indicate: (1) The closer the interference frequency is to the carrier frequency of the working signal, the worse the anti-interference ability of the data link is. (2) Increasing the power of the working signal can improve the anti-interference ability of the data link. (3) Front-door coupling is an important way for EMI to enter the receiver in tactical scenarios. These findings could provide optimized EMI protection for the next generation of UAV data links.
, Available online ,
doi: 10.11884/HPLPB202537.250076
Abstract:
Background Purpose Methods Results Conclusions
Electromagnetic (EM) emissions from electronic devices can inadvertently carry sensitive information, posing significant threats to information security. EM fingerprinting techniques have become vital for security inspection and leakage source localization, yet existing approaches often suffer from poor adaptability across sampling rates and insufficient extraction of high-frequency features.
This study aims to develop a robust EM fingerprint recognition method that maintains high accuracy across different sampling rates while effectively capturing high-frequency characteristics, thereby improving security detection and adaptability in practical scenarios.
We propose an enhanced neural network architecture, termed ELEC-TDNN, which integrates a channel attention mechanism with multi-scale temporal modeling capabilities. A local signal enhancement layer is introduced to improve the representation of subtle EM features. Experiments were conducted on a self-constructed dual-sampling-rate USB device EM emission dataset (1.25 GHz and 500 MHz) to evaluate performance. The evaluation used equal error rate (EER) as the primary metric to measure recognition accuracy under varying frequency conditions.
The proposed ELEC-TDNN achieved superior adaptability and accuracy compared with conventional methods. At 500 MHz, the model attained a minimum EER of 0.35%, while in the high-frequency 1.25 GHz scenario, it achieved an EER of 5.23%. These results indicate that the architecture effectively preserves recognition performance despite significant differences in sampling rates.
By combining attention-based channel feature selection, multi-scale temporal modeling, and local signal enhancement, the method addresses both cross-sampling-rate adaptability and high-frequency feature extraction challenges. This work demonstrates practical value in enhancing EM security detection systems and offers a scalable approach for future EM analysis in multi-rate environments.
Column
- Cover and Contents
- High Power Laser Physics and Technology
- Inertial Confinement Fusion Physics and Technology
- High Power Microwave Technology
- Particle Beams and Accelerator Technology
- Pulsed Power Technology
- Nuclear Science and Engineering
- Advanced Interdisciplinary Science
- Special Column of 5th Symposium on Frontier of HPLPB
Display Method:
2025, 37: 081001.
doi: 10.11884/HPLPB202537.250034
Abstract:
Ross pair and filters stack spectrometers are commonly used to detect hard X-ray spectra. The results of filters stack spectrometer are highly sensitive to the profile of the pre-estimated spectrum, while Ross pair is limited to discrete spectrum. Here we provide a Ross pair-filters stack mixed spectrometer, which combines the advantages of traditional filter stack spectrometers and Ross pairs. Each layer of the filter in the traditional filters stack spectrometer has been replaced with a Ross filter pair. Thus, the discrete spectrum given by Ross pair can be used as the pre-estimated spectrum for the filters stack to solve the entire X-ray spectrum. Numerical and physical experiments using X-ray tube confirm that the present mixed spectrometer can provide more accurate spectral structures compared to traditional filter stack spectrometers. The compact and lightweight design make it widely applicable in hard X-ray spectral measurements.
Ross pair and filters stack spectrometers are commonly used to detect hard X-ray spectra. The results of filters stack spectrometer are highly sensitive to the profile of the pre-estimated spectrum, while Ross pair is limited to discrete spectrum. Here we provide a Ross pair-filters stack mixed spectrometer, which combines the advantages of traditional filter stack spectrometers and Ross pairs. Each layer of the filter in the traditional filters stack spectrometer has been replaced with a Ross filter pair. Thus, the discrete spectrum given by Ross pair can be used as the pre-estimated spectrum for the filters stack to solve the entire X-ray spectrum. Numerical and physical experiments using X-ray tube confirm that the present mixed spectrometer can provide more accurate spectral structures compared to traditional filter stack spectrometers. The compact and lightweight design make it widely applicable in hard X-ray spectral measurements.
2025, 37: 081002.
doi: 10.11884/HPLPB202537.250065
Abstract:
As a new type of laser driver for suppressing laser plasma instability, the low-coherence laser driver holds significant research value in the field of laser inertial confinement fusion. To achieve large-bandwidth and high-power low-coherence pulse parametric amplification, this study provides a detailed analysis of the parametric matching characteristics of DKDP crystals with varying deuteration rates under Type-I collinear phase matching conditions. The fundamental parameters, including phase-matching angles, walk-off angles, and parametric bandwidths, are determined. The theoretical parameter bandwidth of the 58% deuterium-doped DKDP crystal is 180 nm. On this basis, a design for broadband low-temporal-coherence optical parametric amplification based on 58% DKDP crystals is proposed, and the theoretical model and the corresponding numerical model are established by the three-wave coupled equations. Furthermore, an experimental investigation of parametric amplification based on 58%-deuterium-doped DKDP crystals is conducted. The center wavelength of the broadband low-coherence signal light is set at1053 nm, while the pump wavelength is fixed at 532 nm. The spectral width is 40 nm with a gain factor of 2.1. The results show that 58% DKDP crystal has a large gain bandwidth, and combined with the colinear phase-matching method, such crystals are expected to enable large-bandwidth and high-gain amplification of low-coherence light.
As a new type of laser driver for suppressing laser plasma instability, the low-coherence laser driver holds significant research value in the field of laser inertial confinement fusion. To achieve large-bandwidth and high-power low-coherence pulse parametric amplification, this study provides a detailed analysis of the parametric matching characteristics of DKDP crystals with varying deuteration rates under Type-I collinear phase matching conditions. The fundamental parameters, including phase-matching angles, walk-off angles, and parametric bandwidths, are determined. The theoretical parameter bandwidth of the 58% deuterium-doped DKDP crystal is 180 nm. On this basis, a design for broadband low-temporal-coherence optical parametric amplification based on 58% DKDP crystals is proposed, and the theoretical model and the corresponding numerical model are established by the three-wave coupled equations. Furthermore, an experimental investigation of parametric amplification based on 58%-deuterium-doped DKDP crystals is conducted. The center wavelength of the broadband low-coherence signal light is set at
2025, 37: 081003.
doi: 10.11884/HPLPB202537.250103
Abstract:
This article mainly investigated the incident and exit surfaces of terbium gallium garnet (TGG) magneto-optical elements by damaged by the laser with wavelength of1064 nm through pump-probe imaging technology. The damage characteristics of terbium gallium garnet elements under fundamental 1064 nm pulsed laser irradiation were studied. The results indicated that the coated TGG element exhibited a lower damage threshold at the incident surface compared with the exit surface, and the difference in damage morphology between the entrance and exit surface was mainly influenced by laser-induced plasma effects. It was found that the initial damage on the TGG incident surface mainly came from impurities and defects in the coatings, and the separation of the film layer under high energy would occur; The exit surface damage of coated TGG components was mainly induced by impurity defects in the substrate material, and the size of damage pits increased gradually under higher laser energy. By analyzing the influence of factors such as laser pulse energy, plasma effect, and material damage response on the laser damage threshold, this study provided important and reference for improving the anti-damage ability of TGG magneto-optical materials under high-power laser irradiation.
This article mainly investigated the incident and exit surfaces of terbium gallium garnet (TGG) magneto-optical elements by damaged by the laser with wavelength of
2025, 37: 081004.
doi: 10.11884/HPLPB202537.250072
Abstract:
To achieve stable transmission of laser with lower loss, single mode, and single polarization in the mid-infrared band, This paper designs a bend-resistant hollow-core anti-resonant fiber configuration with a double-cladding nested structure. The finite element method is used to optimize the structural parameters, and the transmission characteristics of broadband low-loss single polarization of the fiber are verified through simulation. The confinement loss of this fiber is less than 0.01 dB/km within the wavelength range of 2.9−3.3 μm, and the high-order mode extinction ratio exceeds1000 , and the confinement loss is as low as 0.0014 dB/km at 3 μm wavelength. The symmetry of the fiber structure is destroyed by using different nested tube thicknesses, and the single-polarization characteristic of the fiber is theoretically investigated. Within the wavelength range of 2.996−3.004 μm, the polarization extinction ratio exceeds 10000 , demonstrating an extremely stable single polarization effect. In addition, theoretical analysis indicates that this fiber also has excellent bending resistance performance. When the bending radius in the y-direction is greater than 5 cm, it can still ensure single-polarization laser transmission, and the bending loss is less than 3.11 dB/km. The designed hollow-core anti-resonant fiber configuration has great potential for application in mid-infrared fiber laser and other fields.
To achieve stable transmission of laser with lower loss, single mode, and single polarization in the mid-infrared band, This paper designs a bend-resistant hollow-core anti-resonant fiber configuration with a double-cladding nested structure. The finite element method is used to optimize the structural parameters, and the transmission characteristics of broadband low-loss single polarization of the fiber are verified through simulation. The confinement loss of this fiber is less than 0.01 dB/km within the wavelength range of 2.9−3.3 μm, and the high-order mode extinction ratio exceeds
2025, 37: 082001.
doi: 10.11884/HPLPB202537.240429
Abstract:
In experimental studies of indirect drive inertial confinement fusion, both flat-response X-ray detector (FXRD) and space-resolving flux detector (SRFD) are commonly used to measure the radiation flux. The SRFD can measure radiation flux in localized spatial regions, thus avoiding signal disruption from non-targeted regions. However, direct experimental evidence has long been lacking to determine the consistency between SRFD and FXRD. In this paper, we introduce the experimental design of consistency measurement of the SRFD detector and FXRD detector at Shenguang 100 kJ facility, based on a small-plane target, which considers the field-of-view and signal amplitude of the two detectors. The experimental results show that the average difference in the radiation flux obtained by the two detectors is approximately 4.6%, which shows good consistency. Finally, the radiation flux given by the radiation hydrodynamic simulation is reasonably close to the experiment, with some differences in the behavior at the rising edge and decreasing edge. It is possibly related to the details of the simulation model. This work provides a good foundation for experimental studies related to the precision measurement of X-ray radiation flux in a local spatial region.
In experimental studies of indirect drive inertial confinement fusion, both flat-response X-ray detector (FXRD) and space-resolving flux detector (SRFD) are commonly used to measure the radiation flux. The SRFD can measure radiation flux in localized spatial regions, thus avoiding signal disruption from non-targeted regions. However, direct experimental evidence has long been lacking to determine the consistency between SRFD and FXRD. In this paper, we introduce the experimental design of consistency measurement of the SRFD detector and FXRD detector at Shenguang 100 kJ facility, based on a small-plane target, which considers the field-of-view and signal amplitude of the two detectors. The experimental results show that the average difference in the radiation flux obtained by the two detectors is approximately 4.6%, which shows good consistency. Finally, the radiation flux given by the radiation hydrodynamic simulation is reasonably close to the experiment, with some differences in the behavior at the rising edge and decreasing edge. It is possibly related to the details of the simulation model. This work provides a good foundation for experimental studies related to the precision measurement of X-ray radiation flux in a local spatial region.
2025, 37: 082002.
doi: 10.11884/HPLPB202537.250027
Abstract:
To achieve four-phase image registration, an image registration method based on SIFT (scale invariant features transform) algorithm is proposed in this paper. The method is divided into four steps. Firstly, the feature points of the reference image and the misregistration images are extracted respectively. In this step, the characteristics of 2D-velocity interferometry system for any reflector (VISAR) images are fully considered, and homologous non-fringe images are introduced to obtain more accurate results. The second step is feature points matching. After roughly matching, a two-stepfiltering method composed of angle histograms and feature point distance is designed to achieve accurate matching. The third step involves calculating the transformation parameters based on the final matching results. Finally, the transformation parameters are applied to misregistration images for interpolation transformation to achieve image registration. One of the four-phase images is used as the reference image to register the remaining three images. For nonfringe images, experimental results show that the correlation coefficient between registered images and the reference image increases from 0.5 to above 0.9. For fringe images, the calculation accuracy of wrapped phase improves significantly. Therefore, the algorithm in this paper effectively solves the registration problem of 2D-VISAR four-phase images, laying a foundation for further data processing in the future.
To achieve four-phase image registration, an image registration method based on SIFT (scale invariant features transform) algorithm is proposed in this paper. The method is divided into four steps. Firstly, the feature points of the reference image and the misregistration images are extracted respectively. In this step, the characteristics of 2D-velocity interferometry system for any reflector (VISAR) images are fully considered, and homologous non-fringe images are introduced to obtain more accurate results. The second step is feature points matching. After roughly matching, a two-stepfiltering method composed of angle histograms and feature point distance is designed to achieve accurate matching. The third step involves calculating the transformation parameters based on the final matching results. Finally, the transformation parameters are applied to misregistration images for interpolation transformation to achieve image registration. One of the four-phase images is used as the reference image to register the remaining three images. For nonfringe images, experimental results show that the correlation coefficient between registered images and the reference image increases from 0.5 to above 0.9. For fringe images, the calculation accuracy of wrapped phase improves significantly. Therefore, the algorithm in this paper effectively solves the registration problem of 2D-VISAR four-phase images, laying a foundation for further data processing in the future.
2025, 37: 083001.
doi: 10.11884/HPLPB202537.250030
Abstract:
In order to solve the problem of microwave ignition of solid energetic materials under low power conditions, this paper proposes a low-power high-field microwave ignition technology based on dual-focusing optimization design of rectangular resonant cavity. The developed microwave ignition device consists of a solid-state microwave source, a rectangular resonant cavity, a microwave probe and other components. Among them, the rectangular resonant cavity is fed by a probe, and the energy is focused once by resonance. Combined with the distortion effect of the probe tip on the electric field and the compression effect of the metal stage on the electric field distribution space, the secondary focusing of the energy in the cavity during resonance is achieved, and the electromagnetic compatibility design is used to prevent electromagnetic wave leakage. The simulation and experiment show that the microwave ignition device has multiple operating frequency points in the range of 2−3 GHz and the frequency is adjustable. The maximum field strength can reach MV/m level at 22 W power, enabling effective ignition of small black powder. Compared with the existing device, the ignition power is significantly reduced. The developed low-power and high-field microwave ignition technology can provide a platform for the study of microwave ignition of solid energetic materials.
In order to solve the problem of microwave ignition of solid energetic materials under low power conditions, this paper proposes a low-power high-field microwave ignition technology based on dual-focusing optimization design of rectangular resonant cavity. The developed microwave ignition device consists of a solid-state microwave source, a rectangular resonant cavity, a microwave probe and other components. Among them, the rectangular resonant cavity is fed by a probe, and the energy is focused once by resonance. Combined with the distortion effect of the probe tip on the electric field and the compression effect of the metal stage on the electric field distribution space, the secondary focusing of the energy in the cavity during resonance is achieved, and the electromagnetic compatibility design is used to prevent electromagnetic wave leakage. The simulation and experiment show that the microwave ignition device has multiple operating frequency points in the range of 2−3 GHz and the frequency is adjustable. The maximum field strength can reach MV/m level at 22 W power, enabling effective ignition of small black powder. Compared with the existing device, the ignition power is significantly reduced. The developed low-power and high-field microwave ignition technology can provide a platform for the study of microwave ignition of solid energetic materials.
2025, 37: 083002.
doi: 10.11884/HPLPB202537.250059
Abstract:
Microwave plasma has shown significant advantages in the fields of materials synthesis and chemical catalysis due to its high electron density and power utilization efficiency. To solve the problem that the small reaction area of traditional reactor limits its large-scale application, a three-prism microwave plasma reactor structure is innovatively proposed based on the principle of compressed waveguide. The design adopts a three-port symmetric configuration and introduces a compressed waveguide structure inside the cavity to achieve effective superposition and enhancement of the electric field. In addition, the influence of the port positions and microwave phases on the reflection coefficient and electric field distribution characteristics inside the cavity is systematically analyzed by using the multi-physical field coupling calculation method. The results show that optimizing the port position can reduce the reflection coefficient and improve the efficiency of energy utilization, regulating the port phase can effectively enhance the superposition effect of the electric field, so that the electric field is concentrated and widely distributed in the area of the quartz tube, and the peak field strength is as high as 1.64×105 V/m, which can satisfy the excitation conditions of the large-area plasma, providing a reference for the subsequent research on microwave plasma chemical reaction.
Microwave plasma has shown significant advantages in the fields of materials synthesis and chemical catalysis due to its high electron density and power utilization efficiency. To solve the problem that the small reaction area of traditional reactor limits its large-scale application, a three-prism microwave plasma reactor structure is innovatively proposed based on the principle of compressed waveguide. The design adopts a three-port symmetric configuration and introduces a compressed waveguide structure inside the cavity to achieve effective superposition and enhancement of the electric field. In addition, the influence of the port positions and microwave phases on the reflection coefficient and electric field distribution characteristics inside the cavity is systematically analyzed by using the multi-physical field coupling calculation method. The results show that optimizing the port position can reduce the reflection coefficient and improve the efficiency of energy utilization, regulating the port phase can effectively enhance the superposition effect of the electric field, so that the electric field is concentrated and widely distributed in the area of the quartz tube, and the peak field strength is as high as 1.64×105 V/m, which can satisfy the excitation conditions of the large-area plasma, providing a reference for the subsequent research on microwave plasma chemical reaction.
2025, 37: 083003.
doi: 10.11884/HPLPB202537.250010
Abstract:
Microstrip traveling wave tubes (TWTs) have garnered significant attention due to their potential applications in communication, defense, and industrial systems. This paper presents a compact W-band dual-channel TWT, utilizing a U-shaped microstrip meander-line slow-wave structure (SWS). High-frequency characteristics are analyzed through simulation and cold tests. The results demonstrate that adjusting structural parameters effectively optimizes the S-parameters. Particle-in-cell (PIC) simulations with an 18.8 kV, 0.1 A electron beam predict an output power of 18 W with a gain of 14 dB. Experimental measurements of S-parameters are conducted using three substrate materials: Rogers 5880, quartz, and diamond. The quartz substrate exhibits the closest agreement with simulation results. The results advance the development of the microstrip-based TWTs for high-data-rate communication systems.
2025, 37: 083004.
doi: 10.11884/HPLPB202537.250062
Abstract:
To address the electromagnetic pulse protection requirements of the RF front-end in a complex electromagnetic environment, a strong electromagnetic pulse protection circuit working in the L-band is designed. This circuit uses PIN diode as the core device, adopts a multi-level PIN diode cascaded protection structure, connects each stage through microstrip transmission lines, and optimizes the design. The performance of the circuit under different working conditions is verified by simulation, and its physical test is carried out. The test results show that in the L-band, its insertion loss is less than 0.6 dB, the return loss is more than 11.93 dB, and the standing wave ratio is less than 1.68, indicating good signal transmission performance. Under the injection of a 4 kV square wave pulse, the circuit can respond quickly within 1 ns, and the peak leakage voltage generated by the circuit is 69.636 V. After 2 ns, the stable output voltage of the circuit is less than 20 V, indicating that the circuit has good transient protection capability against fast-edge pulse. Combined with the low-loss characteristics in L-band, the circuit can provide effective electromagnetic pulse protection support for equipment working in L-band.
To address the electromagnetic pulse protection requirements of the RF front-end in a complex electromagnetic environment, a strong electromagnetic pulse protection circuit working in the L-band is designed. This circuit uses PIN diode as the core device, adopts a multi-level PIN diode cascaded protection structure, connects each stage through microstrip transmission lines, and optimizes the design. The performance of the circuit under different working conditions is verified by simulation, and its physical test is carried out. The test results show that in the L-band, its insertion loss is less than 0.6 dB, the return loss is more than 11.93 dB, and the standing wave ratio is less than 1.68, indicating good signal transmission performance. Under the injection of a 4 kV square wave pulse, the circuit can respond quickly within 1 ns, and the peak leakage voltage generated by the circuit is 69.636 V. After 2 ns, the stable output voltage of the circuit is less than 20 V, indicating that the circuit has good transient protection capability against fast-edge pulse. Combined with the low-loss characteristics in L-band, the circuit can provide effective electromagnetic pulse protection support for equipment working in L-band.
2025, 37: 084001.
doi: 10.11884/HPLPB202537.250082
Abstract:
As accelerators increase in scale and complexity, their control networks face challenges such as device proliferation, security management difficulties, and low maintenance efficiency. To address these issues, a control network management system for large-scale accelerators was designed and developed. This system implements three functions: centralized management of control network IP addresses, automated collection of dynamic network information, and network access control. The system prevents IP conflicts through a centralized application and approval mechanism, enables real-time monitoring of device status and precise physical location identification based on switch operational data, and enhances control network access security through IP and port binding. The system is built on a web. architecture, with a front-end developed using the Vue.js framework and a back-end utilizing a hybrid technology stack of Node.js and Python, while MongoDB is employed for data storage. This system has been successfully deployed and is operating stably in the China Spallation Neutron Source (CSNS) accelerator control network, effectively addressing security vulnerabilities and maintenance challenges in network management. It has also established a foundation for network management in CSNS-II.
As accelerators increase in scale and complexity, their control networks face challenges such as device proliferation, security management difficulties, and low maintenance efficiency. To address these issues, a control network management system for large-scale accelerators was designed and developed. This system implements three functions: centralized management of control network IP addresses, automated collection of dynamic network information, and network access control. The system prevents IP conflicts through a centralized application and approval mechanism, enables real-time monitoring of device status and precise physical location identification based on switch operational data, and enhances control network access security through IP and port binding. The system is built on a web. architecture, with a front-end developed using the Vue.js framework and a back-end utilizing a hybrid technology stack of Node.js and Python, while MongoDB is employed for data storage. This system has been successfully deployed and is operating stably in the China Spallation Neutron Source (CSNS) accelerator control network, effectively addressing security vulnerabilities and maintenance challenges in network management. It has also established a foundation for network management in CSNS-II.
Design and validation of a proton beam line based on a rapid-cycling synchrotron for Flash radiation
2025, 37: 084002.
doi: 10.11884/HPLPB202537.250003
Abstract:
We have designed a proton beamline based on a rapid-cycling synchrotron for Flash radiation with ultra-high dose rate. Because proton beams can be extracted within hundreds of nanoseconds in the rapid-cycling synchrotron, its energy can be altered from one cycle to the next with different extraction time. The intended beamline system can achieve layer stacking irradiation at an instantaneous dose rate of 107 Gy/s. Each longitudinal layer requires a different beam intensity. The target is divided longitudinally into different layers, each of which needs a different beam energy, to produce a uniform irradiation field. The system, including a double scatter system, a range compensator, a ripple filter, and a multi-leaf collimator to maximize proton fluence into the target, is simulated using the Monte Carlo software FLUKA. Three different kinds of ripple filters are built for the low, medium, and high energy zones based on the original Bragg peaks to reduce the number of energy layers and shorten the total irradiation duration. These filters transform the spike region into a Gaussian distribution with flat expansion areas of 2 cm, 6 cm, and 20 cm, respectively. Combining the rapid-cycling synchrotron with the layer stacking irradiation provides a novel method for achieving Flash proton irradiation, which delivers an ultra-high dose rate to the target.
We have designed a proton beamline based on a rapid-cycling synchrotron for Flash radiation with ultra-high dose rate. Because proton beams can be extracted within hundreds of nanoseconds in the rapid-cycling synchrotron, its energy can be altered from one cycle to the next with different extraction time. The intended beamline system can achieve layer stacking irradiation at an instantaneous dose rate of 107 Gy/s. Each longitudinal layer requires a different beam intensity. The target is divided longitudinally into different layers, each of which needs a different beam energy, to produce a uniform irradiation field. The system, including a double scatter system, a range compensator, a ripple filter, and a multi-leaf collimator to maximize proton fluence into the target, is simulated using the Monte Carlo software FLUKA. Three different kinds of ripple filters are built for the low, medium, and high energy zones based on the original Bragg peaks to reduce the number of energy layers and shorten the total irradiation duration. These filters transform the spike region into a Gaussian distribution with flat expansion areas of 2 cm, 6 cm, and 20 cm, respectively. Combining the rapid-cycling synchrotron with the layer stacking irradiation provides a novel method for achieving Flash proton irradiation, which delivers an ultra-high dose rate to the target.
2025, 37: 085001.
doi: 10.11884/HPLPB202537.250021
Abstract:
This paper proposes a miniaturized impulse voltage generator that differs from the traditional gas ball gap. It adopts a modular multi-stage structure, using the Marx topology as the main circuit and MOSFET as the main switch. MATLAB is used to fit and modulate lightning impulses or chopped lightning impulses through the nearest-level forced modulation algorithm (NLM). an FPGA controls the modular impulse voltage generator to generate impulse voltage waveforms such as charging voltage, wavefront time, wave tail time, and truncation time, all of wich can be flexibly adjusted by the host computer. The test results show that the maximum output voltage of a single impulse voltage module is 24 kV, with a total of 30 stages of voltage output. When 5 impulse voltage modules are operated in series, a maximum of 150 stages of different voltages can be generated, and the peak voltage can reach −100 kV lightning impulses or chopped lightning impulses.
This paper proposes a miniaturized impulse voltage generator that differs from the traditional gas ball gap. It adopts a modular multi-stage structure, using the Marx topology as the main circuit and MOSFET as the main switch. MATLAB is used to fit and modulate lightning impulses or chopped lightning impulses through the nearest-level forced modulation algorithm (NLM). an FPGA controls the modular impulse voltage generator to generate impulse voltage waveforms such as charging voltage, wavefront time, wave tail time, and truncation time, all of wich can be flexibly adjusted by the host computer. The test results show that the maximum output voltage of a single impulse voltage module is 24 kV, with a total of 30 stages of voltage output. When 5 impulse voltage modules are operated in series, a maximum of 150 stages of different voltages can be generated, and the peak voltage can reach −100 kV lightning impulses or chopped lightning impulses.
Measurement method for areal density of pulsed X-ray photographic images in metal ejection diagnosis
2025, 37: 085002.
doi: 10.11884/HPLPB202537.250025
Abstract:
The ejection phenomenon generated by metal materials under strong impact is an important issue in the field of impact compression research. Pulsed X-ray photography is an important diagnostic testing method for micro jet processes. The use of X-ray images to obtain the surface density of metal material experimental objects and jets under strong impact is an important objective of this type of experiment. A method for measuring the areal density data of ejection X-ray images based on stepped wedges is proposed. The method reduces the influence of white spot noise by median filtering, corrects the unevenness of light field distribution and detector response by using empty field images and obtains the system point spread function by imaging the Roll-Bar object, and uses the imaging system point spread function and an improved Tikhonov regularization based image restoration method to reduce the impact of blur on X-ray images. The processing flow for obtaining the areal density information of ejection X-ray images is provided. The verification of the inversion of areal density in static object experimental images shows that the proposed method can accurately obtain the areal density information of metal ejection experimental X-ray images.
The ejection phenomenon generated by metal materials under strong impact is an important issue in the field of impact compression research. Pulsed X-ray photography is an important diagnostic testing method for micro jet processes. The use of X-ray images to obtain the surface density of metal material experimental objects and jets under strong impact is an important objective of this type of experiment. A method for measuring the areal density data of ejection X-ray images based on stepped wedges is proposed. The method reduces the influence of white spot noise by median filtering, corrects the unevenness of light field distribution and detector response by using empty field images and obtains the system point spread function by imaging the Roll-Bar object, and uses the imaging system point spread function and an improved Tikhonov regularization based image restoration method to reduce the impact of blur on X-ray images. The processing flow for obtaining the areal density information of ejection X-ray images is provided. The verification of the inversion of areal density in static object experimental images shows that the proposed method can accurately obtain the areal density information of metal ejection experimental X-ray images.
2025, 37: 085003.
doi: 10.11884/HPLPB202537.250102
Abstract:
Deionized water, commonly used as insulating dielectric in pulse-forming lines or transmission lines of high-power pulse devices, offers advantages such as a high dielectric constant, high breakdown strength, good self-healing properties, and low cost. However, the solid insulation barriers in deionized water, which support the inner cylinder and provide physical isolation between different dielectrics at the front and rear ends, are often the weak points in high-voltage insulation systems. To investigate the surface flashover characteristics of typical solid insulation materials in deionized water, this study utilized a high-voltage insulation experimental platform with a maximum operating voltage of approximately 900 kV and a pulse rise time of about 100 ns. The study focused on four common solid insulation materials: MC Nylon, polymethyl methacrylate (PMMA), cross-linked polystyrene (CLPS), and high-density polyethylene (HDPE). Using circular plate electrodes and cylindrical samples, the experiments examined the effects of sample material, thickness, voltage duration and surface roughness on flashover voltage and electric field strength. Results show that as the sample thickness increases from 0.5 cm to 2 cm, the flashover voltage increases linearly, while the flashover field strength decreases exponentially. For different materials, the flashover voltage and field strength follow the order: MC Nylon ≥ PMMA > CLPS > HDPE. As the voltage application time shortens, the flashover voltage gradually increases. When the voltage application time is within 100 ns, the flashover voltage remains basically stable. Furthermore, when the surface roughness of the solid material increases from 1.6 μm to 12.5 μm, no significant change in flashover field strength is observed. Based on a comprehensive analysis of flashover field strength data and impact resistance characteristics, MC Nylon demonstrates the best overall.
Deionized water, commonly used as insulating dielectric in pulse-forming lines or transmission lines of high-power pulse devices, offers advantages such as a high dielectric constant, high breakdown strength, good self-healing properties, and low cost. However, the solid insulation barriers in deionized water, which support the inner cylinder and provide physical isolation between different dielectrics at the front and rear ends, are often the weak points in high-voltage insulation systems. To investigate the surface flashover characteristics of typical solid insulation materials in deionized water, this study utilized a high-voltage insulation experimental platform with a maximum operating voltage of approximately 900 kV and a pulse rise time of about 100 ns. The study focused on four common solid insulation materials: MC Nylon, polymethyl methacrylate (PMMA), cross-linked polystyrene (CLPS), and high-density polyethylene (HDPE). Using circular plate electrodes and cylindrical samples, the experiments examined the effects of sample material, thickness, voltage duration and surface roughness on flashover voltage and electric field strength. Results show that as the sample thickness increases from 0.5 cm to 2 cm, the flashover voltage increases linearly, while the flashover field strength decreases exponentially. For different materials, the flashover voltage and field strength follow the order: MC Nylon ≥ PMMA > CLPS > HDPE. As the voltage application time shortens, the flashover voltage gradually increases. When the voltage application time is within 100 ns, the flashover voltage remains basically stable. Furthermore, when the surface roughness of the solid material increases from 1.6 μm to 12.5 μm, no significant change in flashover field strength is observed. Based on a comprehensive analysis of flashover field strength data and impact resistance characteristics, MC Nylon demonstrates the best overall.
2025, 37: 086001.
doi: 10.11884/HPLPB202537.240430
Abstract:
The X-ray beam position monitor (XBPM) can be used to measure the position of beamline synchrotron radiation light. The front-end acquisition circuit of XBPM is mainly used for analog signal acquisition and processing. To meet the demand for precise measurement of synchrotron light position information in the beamline front-end area of high energy photo source (HEPS), an XBPM electronic analog front end (AFE) board card has been developed in this paper. The functions such as current-voltage conversion, range switching, gain control and ADC sampling of XBPM signals were designed and implemented, and a laboratory test platform was built to conduct performance tests on XBPM-AFE. The test results show that the current input range of the I/V conversion module is from 10 nA to 1 mA. When the input current varies by three orders of magnitude, the linear error of the transimmer gain in each range segment remains at a relatively low level. The average relative standard deviation of the measurement results among the four channels is less than 0.46%. The analog-to-digital conversion module can accurately reflect the signal input conditions with changing speeds of over 0.1 s and 1 ms respectively in both slow acquisition and fast acquisition modes.
The X-ray beam position monitor (XBPM) can be used to measure the position of beamline synchrotron radiation light. The front-end acquisition circuit of XBPM is mainly used for analog signal acquisition and processing. To meet the demand for precise measurement of synchrotron light position information in the beamline front-end area of high energy photo source (HEPS), an XBPM electronic analog front end (AFE) board card has been developed in this paper. The functions such as current-voltage conversion, range switching, gain control and ADC sampling of XBPM signals were designed and implemented, and a laboratory test platform was built to conduct performance tests on XBPM-AFE. The test results show that the current input range of the I/V conversion module is from 10 nA to 1 mA. When the input current varies by three orders of magnitude, the linear error of the transimmer gain in each range segment remains at a relatively low level. The average relative standard deviation of the measurement results among the four channels is less than 0.46%. The analog-to-digital conversion module can accurately reflect the signal input conditions with changing speeds of over 0.1 s and 1 ms respectively in both slow acquisition and fast acquisition modes.
2025, 37: 089001.
doi: 10.11884/HPLPB202537.250188
Abstract:
Facing the urgent demand for high-performance, customized electromagnetic protection materials driven by increasingly intelligent electronic information systems, traditional research and development (R&D) models face severe limitations due to complex multi-parameter coupling, high trial-and-error costs, and difficulties in cross-scale design, hindering their ability to meet the need for efficient R&D. Artificial intelligence (AI), leveraging data-driven approaches and algorithmic optimization, offers a transformative paradigm to overcome these limitations. This paper systematically reviews AI-empowered research in electromagnetic protection materials. It begins by analyzing the key characteristics and core challenges in the R&D of these materials, highlighting the high suitability of AI for this domain. Subsequently, it illustrates representative research cases from both forward prediction and inverse design perspectives within the field. Finally, the paper identifies existing challenges concerning data availability, physical interpretability of AI models, and practical application deployment barriers. Specific considerations are proposed in three aspects: constructing specialized electromagnetic material gene databases, developing physics-informed neural networks that integrate data with physical principles, and emphasizing the need to promote domain-specific data sharing and establish standardized protocols, so as to pave the way for the intelligent development of next-generation electromagnetic protection materials.
Facing the urgent demand for high-performance, customized electromagnetic protection materials driven by increasingly intelligent electronic information systems, traditional research and development (R&D) models face severe limitations due to complex multi-parameter coupling, high trial-and-error costs, and difficulties in cross-scale design, hindering their ability to meet the need for efficient R&D. Artificial intelligence (AI), leveraging data-driven approaches and algorithmic optimization, offers a transformative paradigm to overcome these limitations. This paper systematically reviews AI-empowered research in electromagnetic protection materials. It begins by analyzing the key characteristics and core challenges in the R&D of these materials, highlighting the high suitability of AI for this domain. Subsequently, it illustrates representative research cases from both forward prediction and inverse design perspectives within the field. Finally, the paper identifies existing challenges concerning data availability, physical interpretability of AI models, and practical application deployment barriers. Specific considerations are proposed in three aspects: constructing specialized electromagnetic material gene databases, developing physics-informed neural networks that integrate data with physical principles, and emphasizing the need to promote domain-specific data sharing and establish standardized protocols, so as to pave the way for the intelligent development of next-generation electromagnetic protection materials.
2025, 37: 089002.
doi: 10.11884/HPLPB202537.250063
Abstract:
With the rapid development of science and technology, high-speed optical imaging and ultrafast diagnostic techniques have become increasingly important in various fields such as science, industry, defense, and medicine. As an ultrafast optical phenomenon detection instrument, the synchroscan streak camera, when used in conjunction with high-repetition-rate lasers, can achieve high-precision time-synchronized pump-probe experiments. By accumulating and amplifying weak optical signals, it enables high signal-to-noise ratio detection. However, existing synchronous scanning circuits, when operating in long-term mode, accumulate high-frequency noise from signal source devices, and there is a lack of specific impedance matching design methods, which affects the improvement of the time resolution performance of streak camera. This paper comprehensively considers various transformer structures and design schemes, and conducts resonant matching design based on spiral resonators. Through finite element simulation, relevant simulation studies are carried out. By adjusting the parameters of the primary coil of the resonator, the output impedance of the RF power amplifier and the capacitive load are matched. The resonant coupling boost study of the design model shows that a high peak voltage can be output under a certain power input, verifying the effectiveness of the spiral resonant method. The comparative analysis of noise response and time jitter indicates that the design method can further enhance the time resolution performance of synchronous scanning. resolution performance of synchronous scanning.
With the rapid development of science and technology, high-speed optical imaging and ultrafast diagnostic techniques have become increasingly important in various fields such as science, industry, defense, and medicine. As an ultrafast optical phenomenon detection instrument, the synchroscan streak camera, when used in conjunction with high-repetition-rate lasers, can achieve high-precision time-synchronized pump-probe experiments. By accumulating and amplifying weak optical signals, it enables high signal-to-noise ratio detection. However, existing synchronous scanning circuits, when operating in long-term mode, accumulate high-frequency noise from signal source devices, and there is a lack of specific impedance matching design methods, which affects the improvement of the time resolution performance of streak camera. This paper comprehensively considers various transformer structures and design schemes, and conducts resonant matching design based on spiral resonators. Through finite element simulation, relevant simulation studies are carried out. By adjusting the parameters of the primary coil of the resonator, the output impedance of the RF power amplifier and the capacitive load are matched. The resonant coupling boost study of the design model shows that a high peak voltage can be output under a certain power input, verifying the effectiveness of the spiral resonant method. The comparative analysis of noise response and time jitter indicates that the design method can further enhance the time resolution performance of synchronous scanning. resolution performance of synchronous scanning.
2025, 37: 089003.
doi: 10.11884/HPLPB202537.250045
Abstract:
In view of the limitations associated with traditional single-spot laser solid-state phase transformation temperature control methods in complex curved workpieces, this paper proposes a multi-input multi-output (MIMO) temperature decoupling control strategy based on active disturbance rejection control (ADRC). first, a finite element model of multi-spot laser-induced solid-state phase transformation was developed, and a model-order reduction method was applied to extract the key dynamic characteristics of the system, significantly reducing computational complexity and laying a foundation for effective control. Subsequently, to address the high-frequency jitter problem encountered by the conventional fal function within small-error regions, an improved bfal function based on Bernstein polynomials was proposed, thereby enhancing system observation accuracy and disturbance rejection capability. Moreover, an improved particle swarm optimization (PSO) algorithm was used to tune the parameter of ADRC controllers, effectively accelerating the optimization process. Finally, co-simulations conducted on the MATLAB/Simulink and COMSOL platforms demonstrated that the proposed PSO-ADRC controller achieves superior performance in terms of response speed, overshoot reduction, and steady-state accuracy compared to the conventional PID and standard ADRC methods. The method thus provides an efficient and precise solution for multi-spot laser solid-state phase transformation temperature control in complex curved workpieces.
In view of the limitations associated with traditional single-spot laser solid-state phase transformation temperature control methods in complex curved workpieces, this paper proposes a multi-input multi-output (MIMO) temperature decoupling control strategy based on active disturbance rejection control (ADRC). first, a finite element model of multi-spot laser-induced solid-state phase transformation was developed, and a model-order reduction method was applied to extract the key dynamic characteristics of the system, significantly reducing computational complexity and laying a foundation for effective control. Subsequently, to address the high-frequency jitter problem encountered by the conventional fal function within small-error regions, an improved bfal function based on Bernstein polynomials was proposed, thereby enhancing system observation accuracy and disturbance rejection capability. Moreover, an improved particle swarm optimization (PSO) algorithm was used to tune the parameter of ADRC controllers, effectively accelerating the optimization process. Finally, co-simulations conducted on the MATLAB/Simulink and COMSOL platforms demonstrated that the proposed PSO-ADRC controller achieves superior performance in terms of response speed, overshoot reduction, and steady-state accuracy compared to the conventional PID and standard ADRC methods. The method thus provides an efficient and precise solution for multi-spot laser solid-state phase transformation temperature control in complex curved workpieces.
2025, 37: 083005.
doi: 10.11884/HPLPB202537.250089
Abstract:
This paper proposes a compact Q-band relativistic backward wave oscillator (RBWO) operating at low magnetic fields, aiming to advance the miniaturization of high-power microwave (HPM) sources. The device consists of a resonant cavity reflector and two sections of periodic slow-wave structures (SWS), designed in a coaxial configuration. By exploiting the inherent characteristics of the coaxial structure, an optimal inner diameter was selected to enhance power handling capacity while mitigating space charge effects induced by the reduced device size. Through comprehensive simulation and optimization, the device achieved a microwave output power of 470 MW with an efficiency of 39.1% under operational conditions of a guiding magnetic field (0.9 T), a diode voltage of 400 kV, and a beam current of 3 kA. The generated microwave signal exhibited a central frequency of 45 GHz.
This paper proposes a compact Q-band relativistic backward wave oscillator (RBWO) operating at low magnetic fields, aiming to advance the miniaturization of high-power microwave (HPM) sources. The device consists of a resonant cavity reflector and two sections of periodic slow-wave structures (SWS), designed in a coaxial configuration. By exploiting the inherent characteristics of the coaxial structure, an optimal inner diameter was selected to enhance power handling capacity while mitigating space charge effects induced by the reduced device size. Through comprehensive simulation and optimization, the device achieved a microwave output power of 470 MW with an efficiency of 39.1% under operational conditions of a guiding magnetic field (0.9 T), a diode voltage of 400 kV, and a beam current of 3 kA. The generated microwave signal exhibited a central frequency of 45 GHz.
2025, 37: 086002.
doi: 10.11884/HPLPB202537.250100
Abstract:
This study establishes a thermal radiation pulse transport model to quantify the energy release rate and cumulative energy of thermal radiation across temporal variations, spectral bands, and propagation distances through dimensionless processing and numerical simulations. Special emphasis is placed on analyzing the influence of atmospheric transmittance and air density ratios on the spatial distribution of thermal radiation energy, revealing the propagation characteristics of strong explosion-induced thermal radiation in spatial transmission and its wavelength dependency. The results demonstrate that temporally, the cumulative thermal radiation energy increases with time while exhibiting a gradually decreasing growth rate. During the fireball re-ignition phase, the visible band contributes a marginally higher proportion to cumulative energy, whereas the infrared band dominates during the cooling phase. Spatially, the thermal radiation energy decreases with lower altitude as propagation distance extends, until reaching a stabilization threshold where the spatial distribution becomes relatively constant. The developed model enables prediction of thermal radiation energy distribution at specific locations under arbitrary explosion conditions, providing theoretical support for protective design of wavelength-sensitive materials.
This study establishes a thermal radiation pulse transport model to quantify the energy release rate and cumulative energy of thermal radiation across temporal variations, spectral bands, and propagation distances through dimensionless processing and numerical simulations. Special emphasis is placed on analyzing the influence of atmospheric transmittance and air density ratios on the spatial distribution of thermal radiation energy, revealing the propagation characteristics of strong explosion-induced thermal radiation in spatial transmission and its wavelength dependency. The results demonstrate that temporally, the cumulative thermal radiation energy increases with time while exhibiting a gradually decreasing growth rate. During the fireball re-ignition phase, the visible band contributes a marginally higher proportion to cumulative energy, whereas the infrared band dominates during the cooling phase. Spatially, the thermal radiation energy decreases with lower altitude as propagation distance extends, until reaching a stabilization threshold where the spatial distribution becomes relatively constant. The developed model enables prediction of thermal radiation energy distribution at specific locations under arbitrary explosion conditions, providing theoretical support for protective design of wavelength-sensitive materials.
2025, 37: 086003.
doi: 10.11884/HPLPB202537.250083
Abstract:
Artificial radiation belts pose potential threats to spacecraft longevity and performance. High-latitude detonation points can inject large quantities of high-energy particles into Earth's outer radiation belt, which is more susceptible to geomagnetic disturbances compared to the inner radiation belt. Understanding the effects of geomagnetic activity on these particles is of significant importance. This study aims to investigate the diffusion and evolution patterns of electrons in high-L-shell artificial radiation belts under geomagnetic activity, analyzing how geomagnetic disturbances influence electron distribution and decay processes to provide theoretical foundations for spacecraft protection. A three-dimensional artificial radiation belt model was developed based on the VERB3D framework. Numerical simulations were conducted to examine electron diffusion and evolution across three parameters: radial distance, energy, and pitch angle. The analysis focused on geomagnetic effects on plasmasphere morphology, wave field intensity, and wave-particle interactions. Intense geomagnetic activity not only caused significant inward contraction of the plasmasphere but also exponentially enhanced wave field intensities both inside and outside the plasmasphere. This accelerated the diffusion process of artificial radiation belt electrons, leading to rapid flux attenuation and achieving stable distribution states in radial distance, energy, and pitch angle within a relatively short timeframe. However, under sustained geomagnetic influence, the flux of stably distributed high-energy electrons continued to decline. Geomagnetic activity can significantly accelerate the diffusion and decay processes of artificial radiation belts, thereby reducing their hazardous effects on spacecraft. These findings provide new theoretical foundations for spacecraft protection design and hold important reference value for space environment safety assurance.
Artificial radiation belts pose potential threats to spacecraft longevity and performance. High-latitude detonation points can inject large quantities of high-energy particles into Earth's outer radiation belt, which is more susceptible to geomagnetic disturbances compared to the inner radiation belt. Understanding the effects of geomagnetic activity on these particles is of significant importance. This study aims to investigate the diffusion and evolution patterns of electrons in high-L-shell artificial radiation belts under geomagnetic activity, analyzing how geomagnetic disturbances influence electron distribution and decay processes to provide theoretical foundations for spacecraft protection. A three-dimensional artificial radiation belt model was developed based on the VERB3D framework. Numerical simulations were conducted to examine electron diffusion and evolution across three parameters: radial distance, energy, and pitch angle. The analysis focused on geomagnetic effects on plasmasphere morphology, wave field intensity, and wave-particle interactions. Intense geomagnetic activity not only caused significant inward contraction of the plasmasphere but also exponentially enhanced wave field intensities both inside and outside the plasmasphere. This accelerated the diffusion process of artificial radiation belt electrons, leading to rapid flux attenuation and achieving stable distribution states in radial distance, energy, and pitch angle within a relatively short timeframe. However, under sustained geomagnetic influence, the flux of stably distributed high-energy electrons continued to decline. Geomagnetic activity can significantly accelerate the diffusion and decay processes of artificial radiation belts, thereby reducing their hazardous effects on spacecraft. These findings provide new theoretical foundations for spacecraft protection design and hold important reference value for space environment safety assurance.
