High Power Laser and Particle Beams, Volume. 37, Issue 7, 073001(2025)

Design of X-band coaxial gyrotron cavity driven by intense relativistic electron beam

Chenxiang An, Ning Zhou, Kun Chen, Dengpan Wang, Chong Li, Youyou Gui, Yihang Yang, Xinhong Cui, and Yanchao Shi
Author Affiliations
  • Key Laboratory of Advanced Science and Technology on High Power Microwave, Northwest Institute of Nuclear Technology, Xi’an 710024, China
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    Under the driving of explosive-emission cathodes, relativistic gyrotrons frequently suffer from virtual cathode phenomena induced by ultrahigh beam currents (>300 A), where electron beams readily impact the inner conductor surfaces, accompanied by unintended excitations of cyclotron resonance and backward-wave oscillation (BWO) modes. This study systematically investigates the electromagnetic characteristics of an X-band coaxial gyrotron cavity driven by an intense relativistic electron beam (IREB), combining theoretical analysis with three-dimensional particle-in-cell (PIC) simulations. The results demonstrate that stable IREB transmission and TE01 single-mode operation can be achieved through cavity geometry optimization and electron beam parameter matching. The cavity quality factor (Qcav) plays a critical role in suppressing parasitic mode competition: TE21-BWO modes are excited when Qcav<65, while TE31 cyclotron resonance modes emerge when Qcav>90. Stable TE01 single-mode oscillation with an output power of 35 MW (voltage: 300 kV, current: 500 A, transverse-to-longitudinal velocity ratio: 1.2) and efficiency of 34.4% are maintained within the Qcav range of 65-90. Further studies reveal that the cavity exhibits significant robustness against electron beam velocity spread (Δβ<25%), providing critical insights for high-power microwave source design.

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    Chenxiang An, Ning Zhou, Kun Chen, Dengpan Wang, Chong Li, Youyou Gui, Yihang Yang, Xinhong Cui, Yanchao Shi. Design of X-band coaxial gyrotron cavity driven by intense relativistic electron beam[J]. High Power Laser and Particle Beams, 2025, 37(7): 073001

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    Paper Information

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    Received: Mar. 8, 2025

    Accepted: Jun. 1, 2025

    Published Online: Jul. 18, 2025

    The Author Email:

    DOI:10.11884/HPLPB202537.250042

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