Simulation analysis of electron beam performance and beam-wave interaction in megawatt-class gyrotron

Liu Qiao; Lv You; Lu Ruiqi; Zhao Qixiang; Zeng Xu; Zhang Yichi; Feng Jinjun

doi:10.11884/HPLPB202638.250129

Article Contents

Article Navigation > High Power Laser and Particle Beams > 2026 > Accepted Manuscript

Liu Qiao, Lv You, Lu Ruiqi, et al. Simulation analysis of electron beam performance and beam-wave interaction in megawatt-class gyrotron[J]. High Power Laser and Particle Beams. doi: 10.11884/HPLPB202638.250129

Citation:

Liu Qiao, Lv You, Lu Ruiqi, et al. Simulation analysis of electron beam performance and beam-wave interaction in megawatt-class gyrotron[J]. High Power Laser and Particle Beams. doi: 10.11884/HPLPB202638.250129

Citation:

PDF( 5962 KB)

Simulation analysis of electron beam performance and beam-wave interaction in megawatt-class gyrotron

doi: 10.11884/HPLPB202638.250129

Liu Qiao^1
,,
Lv You^{2
,
,},
Lu Ruiqi³,
Zhao Qixiang^{1, 3},
Zeng Xu¹,
Zhang Yichi¹,
Feng Jinjun¹

1.
National Key Laboratory of Science and Technology on Vacuum Electronics, Beijing Vacuum Electronics Research Institute, Beijing 100015, China
2.
School of Materials Science and Engineering, Guilin University of Electronic Technology, Guilin 541004, China
3.
School of Information and Communication, Guilin University of Electronic Technology, Guilin 541004, China

Received Date: 2025-04-26
Accepted Date: 2025-07-29
Rev Recd Date: 2025-10-06

Available Online: 2025-12-15

Abstract

Abstract

Background
The gyrotron is a relativistic nonlinear device capable of generating high-power electromagnetic radiation in the millimeter-wave and terahertz frequency ranges. In most operating magnetically confined thermonuclear fusion reactors (ECH&CD), high-power gyrotrons serve as the core microwave source devices for their electron cyclotron wave heating and current drive systems. For high-power gyrotrons, the high-frequency cavity must operate in a high-order whispering gallery mode to meet the power capacity requirements. However, high order mode operation conversely introduces severe mode competition. Electron beam performance is a major factor affecting the mode competition, further limiting their efficient and stable operation, particularly in long-pulse or continuous-wave regimes. Therefore, it is essential to investigate the impact of megawatt-level gyrotron electron beam performance on beam-wave interaction.
Method
This paper comprehensively considers electron beam performance (velocity spread, beam thickness, space charge effects, oscillation startup process, single/double-anode configuration) and establishes a sophisticated time-domain, multi-mode, multi-frequency self-consistent nonlinear beam-wave interaction model.
Purpose
The study focuses on a self-developed megawatt-level 170 GHz gyrotron operating at TE_25,10 mode, analyzing the structural parameter variations of the high-frequency cavity, the start-oscillation current, and the mode competition in single/dual-anode electron beam modulation.
Results
Under operating conditions of 80 kV beam voltage, 40 A beam current, 6.72 T magnetic field, and a velocity ratio of 1.3, the output power reaches 1.35 MW with an interaction efficiency of 42.2%.
Conclusion
Numerical simulations demonstrate that the dual-anode modulation method significantly suppresses mode competition. The successful demonstration of this device establishes a foundation for further studies on higher power and higher-frequency gyrotron.
- mode competition,
- thermonuclear fusion reactors,
- dual-anode electron gun,
- megawatt-class gyrotron

FullText(HTML)

References(24)

References

[1]	李志良, 冯进军, 刘本田, 等. 国际热核聚变装置用回旋管的现状及技术分析[J]. 真空电子技术, 2012(2): 47-54 Li Zhiliang, Feng Jinjun, Liu Bentian, et al. Current status and technical analysis of gyrotron for fusion applications[J]. Vacuum Electronics, 2012(2): 47-54
[2]	安晨翔, 周宁, 陈坤, 等. 相对论强流电子束驱动的X波段同轴回旋管腔体设计[J]. 强激光与粒子束, 2025, 37: 073001 doi: 10.11884/HPLPB202537.250042 An Chenxiang, Zhou Ning, Chen Kun, et al. Design of X-band coaxial gyrotron cavity driven by intense relativistic electron beam[J]. High Power Laser and Particle Beams, 2025, 37: 073001 doi: 10.11884/HPLPB202537.250042
[3]	胡林林, 孙迪敏, 黄麒力, 等. 105/140 GHz双频兆瓦回旋管实现1.0 MW脉冲输出[J]. 强激光与粒子束, 2023, 35: 023001 doi: 10.11884/HPLPB202335.220388 Hu Linlin, Sun Dimin, Huang Qili, et al. 1.0 MW pulse power achieved in 105/140 GHz dual-frequency MW-level gyrotron[J]. High Power Laser and Particle Beams, 2023, 35: 023001 doi: 10.11884/HPLPB202335.220388
[4]	Kariya T, Minami R, Imai T, et al. Development of high power gyrotrons for advanced fusion devices[J]. Nuclear Fusion, 2019, 59: 066009. doi: 10.1088/1741-4326/ab0e2c
[5]	Thumm M K A, Denisov G G, Sakamoto K, et al. High-power gyrotrons for electron cyclotron heating and current drive[J]. Nuclear Fusion, 2019, 59: 073001. doi: 10.1088/1741-4326/ab2005
[6]	Kariya T, Imai T, Minami R, et al. Development of over-MW gyrotrons for fusion at 14 GHz to sub-THz frequencies[J]. Nuclear Fusion, 2017, 57: 066001. doi: 10.1088/1741-4326/aa6875
[7]	Idei H, Kariya T, Imai T, et al. Fully non-inductive second harmonic electron cyclotron plasma ramp-up in the QUEST spherical tokamak[J]. Nuclear Fusion, 2017, 57: 126045. doi: 10.1088/1741-4326/aa7c20
[8]	Nakashima Y, Ichimura K, Islam M S, et al. Recent progress of divertor simulation research using the GAMMA 10/PDX tandem mirror[J]. Nuclear Fusion, 2017, 57: 116033. doi: 10.1088/1741-4326/aa7cb4
[9]	Xu Handong, Wang Xiaojie, Zhang Jian, et al. Recent progress of the development of a long pulse 140GHz ECRH system on EAST[J]. EPJ Web of Conferences, 2019, 203: 04002. doi: 10.1051/epjconf/201920304002
[10]	Erckmann V, Brand P, Braune H, et al. Electron cyclotron heating for W7-X: physics and technology[J]. Fusion Science and Technology, 2007, 52(2): 291-312. doi: 10.13182/FST07-A1508
[11]	Felch K, Blank M, Borchard P, et al. Recent ITER-relevant gyrotron tests[J]. Journal of Physics: Conference Series, 2005, 25(1): 13-23.
[12]	Dammertz G, Alberti S, Arnold A, et al. Development of a 140-GHz 1-MW continuous wave gyrotron for the W7-X stellarator[J]. IEEE Transactions on Plasma Science, 2002, 30(3): 808-818. doi: 10.1109/TPS.2002.801509
[13]	Gantenbein G, Erckmann V, Illy S, et al. 140 GHz, 1 MW CW gyrotron development for fusion applications—Progress and recent results[J]. Journal of Infrared, Millimeter, and Terahertz Waves, 2011, 32(3): 320-328. doi: 10.1007/s10762-010-9749-2
[14]	Dammertz G, Alberti S, Bariou D, et al. 140 GHz high-power gyrotron development for the stellarator W7-X[J]. Fusion Engineering and Design, 2005, 74(1/4): 217-221.
[15]	Felch K, Blank M, Borchard P, et al. Long-pulse and CW tests of a 110-GHz gyrotron with an internal, quasi-optical converter[J]. IEEE Transactions on Plasma Science, 1996, 24(3): 558-569. doi: 10.1109/27.532938
[16]	Felch K, Blank M, Borchard P, et al. Operating experience on six 110 GHz, 1 MW gyrotrons for ECH applications[J]. Nuclear Fusion, 2008, 48: 054008. doi: 10.1088/0029-5515/48/5/054008
[17]	Lohr J, Cengher M, Doane J L, et al. The multiple gyrotron system on the DIII-D tokamak[J]. Journal of Infrared, Millimeter, and Terahertz Waves, 2011, 32(3): 253-273. doi: 10.1007/s10762-010-9706-0
[18]	Bigot B. Progress toward ITER’s first plasma[J]. Nuclear Fusion, 2019, 59: 112001. doi: 10.1088/1741-4326/ab0f84
[19]	Oda Y, Ikeda R, Kajiwara K, et al. Development of the first ITER gyrotron in QST[J]. Nuclear Fusion, 2019, 59: 086014. doi: 10.1088/1741-4326/ab22c2
[20]	Krasilnikov A V, Abdyuhanov I M, Aleksandrov E V, et al. Progress with the ITER project activity in Russia[J]. Nuclear Fusion, 2015, 55: 104007. doi: 10.1088/0029-5515/55/10/104007
[21]	Ioannidis Z C, Rzesnicki T, Albajar F, et al. CW experiments with the EU 1-MW, 170-GHz industrial prototype gyrotron for ITER at KIT[J]. IEEE Transactions on Electron Devices, 2017, 64(9): 3885-3892. doi: 10.1109/TED.2017.2730242
[22]	Botton M, Antonsen T M, Levush B, et al. MAGY: a time-dependent code for simulation of slow and fast microwave sources[J]. IEEE Transactions on Plasma Science, 1998, 26(3): 882-892. doi: 10.1109/27.700860
[23]	刘巧. 高功率回旋管多模自洽非线性问题研究[D]. 成都: 电子科技大学, 2020: 36-45 Liu Qiao. Multi-mode self-consistent non-linear research on high-power gyrotron[D]. Chengdu: University of Electronic Science and Technology of China, 2020: 36-45
[24]	Liu Yinghui, Liu Qiao, Niu Xinjian, et al. Design and experiment on a 95-GHz 400 kW-level gyrotron[J]. IEEE Transactions on Electron Devices, 2021, 68(1): 434-437. doi: 10.1109/TED.2020.3036324