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回旋振荡管产生高功率毫米波、亚毫米波,是受控核聚变等离子体加热和电流驱动,是等离子体诊断、太空垃圾处理、高密度数据通信、核磁共振波谱、高分辨率雷达和拒止武器等应用领域不可替代的高效电磁辐射源[1-4]。目前,100~200 GHz频段的兆瓦级回旋振荡管[1, 5]凭借在电子回旋谐振加热和电流驱动等方面的出色表现成为磁约束受控核聚变加热系统的首选波源,受到越来越多的专家学者的关注。随着工作频率和功率的进一步提高,回旋振荡管需要高次模工作,这将使工作模式与竞争模式间分割度减小,带来强烈的模式竞争,降低回旋振荡管的工作效率和稳定性;高电压、大电流工作,受空间电荷效应和枪区自激振荡等因素的影响,电子光学系统的主要指标参数零散进一步加剧,影响整管的工作性能。因此,有效抑制模式竞争和设计高质量电子注是兆瓦级回旋振荡管面临的突出问题。探索高性能、有效抑制非工作模式的谐振腔,设计高质量、大功率电子枪是开展核聚变用兆瓦级回旋振荡管研究的重要内容[6-7]。
本文以基于耦合波理论的回旋管自洽非线性理论为基础,编制回旋振荡管冷、热腔模拟代码,以此为工具,通过考察TE模式谱、注-波耦合系数和工作模式及其附近模式竞争模式的起振电流,设计出了有效抑制非工作模式、高效互作用的170 GHz兆瓦级回旋振荡管。此外,建立电子注速度零散模型,研究了速度零散对该只回旋振荡管工作性能的影响,为设计满足互作用需要的高质量电子光学系统提供理论参考。
Design and Study of 170 GHz Gyrotron with MW Power
doi: 10.3969/j.issn.1001-0548.2018.06.008
- Received Date: 2017-05-31
- Rev Recd Date: 2018-01-30
- Publish Date: 2018-11-01
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Key words:
- efficiency /
- gyrotron /
- mode competition /
- starting current
Abstract: Based on the theories of generalized transmission line and electron cyclotron resonance maser, the TE32, 12 mode is selected as the operating mode of a 170 GHz megawatt gyrotron by investigating the mode spectrum and studying the beam-wave coupling coefficient and the start-current of the modes carefully. Through appropriately arranging the parameters of the beam, the transient modes in the high order mode resonator are suppressed effectively. And through designing the gradual sections of a kind of taped cavity, the parasitic modes are suppressed furthest. As a result, an output power of 1.8 MW, corresponding to 50% efficiency, and an oscillation frequency of 170.18 GHz have been achieved with a pitch factor 1.3, radius of guiding center 9.4mm, 80 kV, 45A helical electron beam at a guiding magnetic field of 6.715T. At the same time, we have also set up a velocity-spread model suitable to actual circumstances and discussed the performance impact to the gyrotron.
Citation: | LEI Chao-jun, LIU Ying-hui, ZHANG Shuang-shi, MENG Lin, LI Hong-fu. Design and Study of 170 GHz Gyrotron with MW Power[J]. Journal of University of Electronic Science and Technology of China, 2018, 47(6): 847-852. doi: 10.3969/j.issn.1001-0548.2018.06.008 |