High-power pulsed gyrotron for 300 GHz-band collective Thomson scattering diagnostics in the Large Helical Device
High-power pulsed gyrotron for 300 GHz-band collective Thomson scattering diagnostics in the Large Helical Device
复制标题
用于大型螺旋装置中 300 GHz 频带集体汤姆逊散射诊断的高功率脉冲回旋管
DOI：
10.1088/0029-5515/55/1/013002
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发表时间：
2015
期刊：
影响因子：
3.3
通讯作者：
Kenji Tanaka and Masaki Nishiura
中科院分区：
文献类型：
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作者：
Yuusuke Yamaguchi;Teruo Saito;Yoshinori Tatematsu;Shinji Ikeuchi;Vladimir N. Manuilov;Jun Kasa;Masaki Kotera;Toshitaka Idehara;Shin Kubo;Takashi Shimozuma;Kenji Tanaka and Masaki Nishiura
研制了一种高功率脉冲回旋管，用于产生300 GHz波段集体汤姆逊散射（CTS）探测波。在该频率范围内，避免模式竞争对于实现具有窄频率带宽的高功率和稳定振荡至关重要。研究了一种适度过模腔，以确保所需模式与相邻模式的充分隔离，并同时实现高功率输出。设计了TE 14，2工作模式的腔体、具有强流层流电子束的电子枪和内模放电管。实验观察到TE 14，2模式的振荡对于模式竞争足够强，并且提供具有足够稳定性的高功率。与电子束特性相关的振荡特性与数值特性进行了比较，以找到最佳的操作条件。结果表明，在294 GHz，65 kV/14 A电子束下，最大输出功率为246 kW的单模工作，效率为1.27%。辐射模式被证实是高度高斯。目前受电源限制的130 kW脉冲的持续时间延长至30 µs。实验结果验证了我们的设计概念，并表明实现更高的功率和更长的脉冲，走向实际使用的300 GHz的CTS诊断回旋管的潜力。
A high-power pulse gyrotron was developed to generate a probe wave for 300 GHz-band collective Thomson scattering (CTS) diagnostics in the Large Helical Device. In this frequency range, avoiding mode competition is critical to realizing high-power and stable oscillation with a narrow frequency bandwidth. A moderately over-moded cavity was investigated to ensure sufficient isolation of a desired mode from neighbouring modes, and to achieve high power output simultaneously. A cavity with the TE 14, 2 operation mode, a triode electron gun with an intense laminar electron beam, and an internal mode convertor were designed to construct a prototype tube. It was experimentally observed that oscillation of the TE 14, 2 mode was strong enough for mode competition, and provided high power with sufficient stability. The oscillation characteristics associated with the electron beam properties were compared with the numerical characteristics to find an optimum operating condition. As a result, single-mode operation with maximum output power of 246 kW was demonstrated at 294 GHz with 65 kV/14 A electron beam, yielding efficiency of∼ 27%. The radiation pattern was confirmed to be highly Gaussian. The duration of the 130 kW pulse, which is presently limited by the power supply, was extended up to 30 µs. The experimental results validate our design concept and indicate the potential for realizing a gyrotron with higher power and longer pulse toward practical use in 300 GHz CTS diagnostics.