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

An Chenxiang; Zhou Ning; Chen Kun; Wang Dengpan; Li Chong; Gui Youyou; Yang Yihang; Cui Xinhong; Shi Yanchao

doi:10.11884/HPLPB202537.250042

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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. doi: 10.11884/HPLPB202537.250042

Citation:

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. doi: 10.11884/HPLPB202537.250042

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

doi: 10.11884/HPLPB202537.250042

Key Laboratory of Advanced Science and Technology on High Power Microwave, Northwest Institute of Nuclear Technology, Xi’an 710024, China

Received Date: 2025-03-08
Accepted Date: 2025-06-01
Rev Recd Date: 2025-06-01

Available Online: 2025-06-16

Abstract

Abstract

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 (Q_cav) plays a critical role in suppressing parasitic mode competition: TE₂₁-BWO modes are excited when Q_cav＜65, while TE₃₁ cyclotron resonance modes emerge when Q_cav＞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 Q_cav 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.
- relativistic gyrotron,
- intense relativistic electron beam,
- mode competition,
- 3D-particle-in-cell simulation

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References(21)

References

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