Email alert
RSSLatest Articles
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/HPLPB202537.250071
Abstract:
Background Purpose Methods Results Conclusions
The Vlasov equation is a cornerstone in plasma physics, governing the evolution of distribution functions in high-temperature, collisionless plasmas. Conventional numerical methods, including Eulerian and Lagrangian approaches, often encounter severe computational challenges due to the rapid increase in cost with fine grid resolutions and the curse of dimensionality. These limitations restrict their effectiveness in large-scale kinetic plasma simulations needed in fusion research and space plasma studies.
This work aims to develop an efficient and scalable computational framework for solving the Vlasov equation that mitigates the drawbacks of traditional methods. The study particularly addresses the need for maintaining accuracy and physical consistency while significantly reducing computational costs in high-dimensional simulations. An approach based on the physics-informed Fourier neural operator (PFNO) is introduced.
The method integrates the high-dimensional function mapping ability of the fourier neural operator with the physical constraints of the Vlasov equation. A physics-informed loss function is constructed to enforce mass, momentum, and energy conservation laws. The framework was evaluated through benchmark tests against finite element and spectral solvers, and its parallel performance was assessed on large-scale computing platforms.
The PFNO approach demonstrates accuracy comparable to conventional solvers while achieving computational efficiency improvements of one to two orders of magnitude. The method shows strong generalization under sparse-data conditions, exhibits grid independence, and scales effectively in parallel computing environments, enabling efficient treatment of high-dimensional plasma dynamics. The study presents a novel paradigm for solving high-dimensional Vlasov equations by combining deep learning operators with physical principles.
The PFNO framework enhances efficiency without sacrificing physical accuracy, making it a promising tool for applications in inertial confinement fusion, astrophysical plasma modeling, and space plasma simulations. Future research directions include extension to multi-species and relativistic plasma systems.
, Available online , doi: 10.11884/HPLPB202537.250161
Abstract:
Background Purpose Methods Results Conclusions
The fast orbit feedback (FOFB) system of the high energy photon source (HEPS) has been developed for the beam orbit control in its storage ring. It mainly consists of beam position monitors (BPMs), the algorithms of fast orbit controller (FOC) and fast correction units. To support HEPS commissioning, we have developed a high-performance signal generator to complete the simulation of beam signals.
The developed signal source includes four output ports with independently adjustable signal amplitudes and synchronous triggers. Its goal is to simulate the timing signals, and enable the simulation output of BPM signals under real beam conditions in the laboratory without beam, with the advantages of simple structure, low cost and high repeatability.
The core of the signal source is an FPGA board. Firstly, a 250 MHz clock signal with a 25% duty cycle was generated by the PLL and directly routed through the MRCC pin. After completing the impedance matching, the RF signal was processed via differential circuit to obtain the required simulated beam signals. Then, the required signals were amplified using the RF amplifier. After the 1∶4 power division, beam signals with four adjustable amplitudes output channels were finally acquired. The trigger signal was supplied directly from the FPGA I/O pins configured for LVCMOS33 operation at 3.3 V, to meet the required LVTTL of BPM electronics.
Based on the beam current characteristics of the HEPS storage ring, we tested the beam signal simulation performance of HEPS storage ring with a frequency of 220 kHz and different patterns during the experiment. In addition, the simulation performance of the single trigger signal and BEPCII collision zone with a frequency of 1.21 MHz has also been tested. The test results showed that the developed signal source could simulate the beam signal well and meet the design requirements. Then, we tested the pattern dependence of HEPS BPM electronics with this signal source. The results showed that there was no pattern dependence effect in the HEPS BPM electronics used in this experiment.
This signal generator could be used to assist in the logical design and correctness of DBPM, to debug the data transmission and control logic between the DBPM and FOFB, and to test the latency of the FOFB system. Based on this system, the debugging difficulty of BPM and FOFB systems could be reduced and accelerate the deployment of the FOFB system.
Modeling and calculation of radiation effects of high-energy rays on PCB inside a shielded enclosure
, Available online , doi: 10.11884/HPLPB202537.250098
Abstract:
Background Purpose Methods Results Conclusions
X/γ-ray irradiation of an electronic system shielding box will penetrate the box body, generate photoelectrons or Compton electrons on the surface layers or inside the system, and excite electromagnetic pulses. These particles or electromagnetic fields will interfere with or even damage the sensitive electronic components of the electronic system inside the box, affecting the regular operation of the electronic system.
To rapidly assess the particle and electromagnetic environment inside electronic systems under radiation exposure and enable timely protective measures that mitigate radiation-induced damage and ensure reliable operation.
We present a theoretical analysis of irradiation responses arising from two coupling mechanisms: electromagnetic pulses excited by primary particles within the cavity of a shielded enclosure and their field-to-circuit coupling to a printed circuit board (PCB), and direct multi-layer penetration coupling of ionizing radiation. Equivalent-circuit models were constructed to represent these coupling paths, and transient current responses were calculated analytically.
The transient current responses of the shielded enclosure under high-energy radiation, computed using the equivalent-circuit approach, reproduce the trends observed in published experimental measurements and exhibit approximate numerical agreement.
The results validate the proposed theoretical modeling approach, showing that analytical equivalent-circuit analysis can provide rapid, simulation-free estimates of radiation effects on electronic systems. The method can be extended to scenarios that more closely match practical applications.
, Available online , doi: 10.11884/HPLPB202537.250122
Abstract:
Background Purpose Methods Results Conclusions
Pulse drive sources are critical components of high-power microwave systems. Existing drive sources based on Tesla+PFL or LTD technology offer good waveform quality but are limited by their large size and weight. PFN-Marx technology sequentially stacks voltages during pulse discharge, which requires relatively low insulation and makes it an ideal technical approach for drive source miniaturization. However, current PFN-Marx-based drive sources struggle to balance compact structural design with output waveform quality.
This study aims to design a compact high-power pulse drive source based on PFN-Marx technology to meet the requirements of a specific high-power microwave system.
To achieve this goal, a 7-stage unipolar pulse charging PFN-Marx generator is employed, with a high-power constant-current charging power supply powered by lithium batteries used to charge the primary capacitor of the Tesla transformer. The PFN modules are designed with identical charging loop inductors to ensure synchronized pulse charging waveforms, and their modular structure allows for flexible scalability. Additionally, the air-core Tesla transformer (with a coupling coefficient greater than 0.8) is integrated with the PFN-Marx within a high-voltage chamber filled with SF6 gas to ensure insulation.
The results show that the drive source outputs a single pulse energy of 45.6 J, and can output a quasi-square wave pulse at a 75 Ω load, with an amplitude of −189.2 kV, a pulse width of 93.2 ns, a rise time of 8.4 ns, and a peak power of 477 MW. The lithium-ion battery charging and control power supply has dimensions of 482 mm×443 mm×177 mm and weighs 12.6 kg; the integrated Tesla transformer and PFN-Marx generator have dimensions of ϕ370 mm×848 mm and weigh 28.7 kg. At a repetition rate of 5 Hz, the average output voltage is −183.4 kV, with a voltage dispersion of 4.1%.
Therefore, this compact PFN-Marx-based pulse drive source achieves both miniaturization and high-quality waveform output, laying the foundation for the development of higher-power and higher-performance compact pulse drive sources.
, Available online , doi: 10.11884/HPLPB202537.250149
Abstract:
Background Purpose Methods Results Conclusions
The high peak power and wide spectral characteristics of high-power radar may cause unintended interference to communication systems operating in adjacent frequency bands.
This study aims to clarify the effects of key LFM waveform parameters on interference mechanisms and to describe their governing patterns.
A closed-loop injection platform based on software-defined radio (SDR) was developed to inject synthesized LFM waveforms into a QPSK receiver. Error vector magnitude (EVM) serves as the performance metric, while pulse width, pulse period, and chirp bandwidth are varied systematically under fixed duty-cycle constraints.
Results indicate that increasing the duty cycle significantly raises the EVM value, although its growth moderates beyond a 30% duty cycle. Under constant duty cycles, pulse-period variations show negligible influence on EVM. As chirp bandwidth increases from 1 MHz to 3 MHz, the EVM decreases from −10.5 dB to −19.8 dB, a reduction of 9.3 dB, but remains nearly constant with further bandwidth expansion to 10 MHz.
These findings offer critical insights into radar-communication spectrum coexistence and anti-interference system design, while confirming the effectiveness of SDR-based platforms for investigating high-power microwave (HPM) interference effects.
, Available online , doi: 10.11884/HPLPB202537.250160
Abstract:
Background Purpose Methods Results Conclusions
Traveling-wave tubes (TWTs) are widely applied in radar, imaging, and military systems owing to their excellent amplification characteristics. Miniaturization and integration are critical to the future of TWTs, with multi-channel slow-wave structures (SWSs) forming the foundation for their realization in high-power vacuum electronic devices.
To provide design insights for multi-channel TWTs and simultaneously enhance their output power, a W-band folded-waveguide TWT with dual electron beams and H-plane power combining was proposed.
Three-dimensional electromagnetic simulations in CST were conducted to verify the high-frequency characteristics, electric field distribution, and amplification performance of the proposed SWS, thereby confirming the validity of the design.
Results indicate that the designed TWT achieves a transmission bandwidth of 10 GHz. With an electron beam voltage of 17.9 kV and a current of 0.35 A, the output power reaches 450 W at 94 GHz, corresponding to an efficiency of 7.18% and a gain of 23.5 dB. Moreover, under fixed beam voltage and current, the TWT delivers over 200 W output power across 91–99 GHz, with a 3 dB bandwidth of 91–98.5 GHz. The particle voltage distribution after modulation further validates the mode analysis.
These results demonstrate the feasibility of compact dual-beam power-combining structures and provide useful guidance for the design of future multi-channel TWTs.
, Available online , doi: 10.11884/HPLPB202537.250138
Abstract:
Background Purpose Methods Results Conclusions
High-power microwave (HPM) pulses, which can interfere with or damage electronic components and circuits, have attracted considerable research interest in recent years. Aperture coupling represents a primary mechanism for such pulses to penetrate shielded metallic enclosures, significantly affecting the electromagnetic compatibility and resilience of electronic systems. Although substantial studies have focused on shielding effectiveness and resonant behaviors, the spatial distribution of coupling parameters—particularly the extent of strongly coupled regions within the cavity—remains inadequately investigated. This paper proposes a quantitative metric termed “the coverage rate of strong-coupled region” to better evaluate HPM backdoor coupling effects.
The objective is to systematically examine the influence of key HPM waveform parameters on this coverage rate within a representative metallic cavity.
A three-dimensional simulation model of a rectangular metallic cavity with an aperture was developed using the finite-difference time-domain (FDTD) method. The internal field distribution was monitored via an array of electric field probes. Numerical simulations were performed to assess the effects of various HPM parameters, including frequency, pulse width, the pulse rise time, and polarization angle, on the coverage of strongly coupled regions.
The coverage rate was markedly higher at the cavity’s inherent resonant frequencies than at non-resonant frequencies. Increasing the pulse width led to a saturation of coverage beyond a specific threshold. Variations in polarization angle from horizontal to vertical considerably enhanced the coverage, with vertical polarization yielding the maximum value. Superimposing multiple resonant frequencies effectively compensated for weakly coupled areas, further increasing the overall coverage. In contrast, the pulse rise time had a negligible effect on the coverage rate. The proposed the coverage rate of strong-coupled region effectively addresses the practical dilemma wherein strong local coupling does not necessarily lead to significant system-level effects.
This metric provides a quantitative basis for optimizing the alignment between sensitive components and highly coupled zones. Frequency and polarization are identified as decisive parameters for enhancing coupling effectiveness, while pulse width and multi-frequency excitation can be utilized to achieve more uniform and robust coupling coverage. These findings offer valuable guidance for the design and assessment of HPM protection measures and electromagnetic compatibility analysis.
