Development of Frequency Tunable, Submillimeter Wave Gyrotrons and Their Application to Scattering Measurement of Plasma

回旋管是覆盖毫米和亚毫米波长范围的高功率源。我们正计划发展高频回旋谐波回旋管及其在等离子体散射测量中的应用。亚毫米波回旋管的研制我们制作了一个8-12 T的超导磁体，并设计了一个电子枪和一个圆柱形谐振腔来构成回旋管。我们对按此设计制作的回旋管进行了测试，得到了以下结果。(1)一种新的谐波回旋管产生了亚毫米波，二次谐波输出功率。其最高频率为404 GHz（对应波长为0.75 mm），功率为几kW。悉尼大学的IVA回旋管实现了高达516 GHz的高频运行，这是稳定回旋管的世界纪录。这项工作是与我们小组合作完成的。(2)回旋加速器谐波操作 关于我们 在354 GHz（TE_ cavity mode）下观察到了3 ~ 3rd<161>，这是高频回旋管所必需的。我们研制的回旋潘尼管在三次谐波共振下，在高频（~ 140 GHz）下产生了高功率（~ 3.3kW）。(3)在354 GHz（对应波长为0.85 mm）的二次谐波下，我们成功地实现了600 msec的长脉冲运转。该操作用于等离子体的散射测量。(4)计算机模拟结果显示了基波和二次谐波之间的模式竞争。实验结果得到了亚毫米波回旋管的证实。找到了高频回旋管作为亚毫米波源所必需的二次谐波单模工作的条件.亚毫米波回旋管在等离子体散射测量中的应用（1）利用回旋管的输出研制了准光路元件，如准光天线。该元件已用于等离子体散射测量系统中。(2)我们已经建立了系统，使用我们的回旋管作为电源，并将其应用到国家聚变科学研究所的螺旋系统（CHS），并成功地观察到自发激发，低频漂移波。少

A gyrotron is a high power source covering millimeter and submillimeter wavelength ranges. We are planning the development of high frequency, cyclotron harmonic gyrotrons and their application to scattering measurement of plasma.1. Development of a gyrotron covering a submillimeter wavelength rangeWe have made up a 8-12 T superconducting magnet which is optimized for a gyrotron and designed an electron gun and a cylindrical cavity to construct the gyrotron tube. We have tested the gyrotrons made on the basis of the designs and obtained following results.(1) A new harmonic gyrotron has produced a submillimeter wave, output power at the 2nd harmonic resonance. Its maximum frequency is 404 GHz (the corresponding wavelength is 0.75 mm) and its power is several kW. Gyrotron IVA of University of Sydney has achieved high frequency operations up to 516 GHz, which is the world record for a stable gyrotron. The work was done under collaboration with our group.(2) Cyclotron harmonic operations up … More to 3rd have been observed at 354 GHz (TE_<161> cavity mode), which are necessary for a high frequency gyrotron. Our gyro-peniotron has produced a high power (-3.3kW) at a high frequency (-140 GHz) under the 3rd harmonic resonance.(3) We have successfully done a long pulse operation up to 600 msec under the second harmonic operation at 354 GHz (the corresponding wavelength is 0.85 mm). The operation is used for scattering measurement of plasma.(4) Computer simulation results show the mode competition between the fundamental and the second harmonic operations. The results are confirmed by using our submillimeter wave gryotron. We have found the conditions for single mode operation at the second harmonic, which is necessary for high frequency gyrotron as a submillimeter wave source.2. Application of a submillimeter wave gyrotron to scattering measurement of plasma(1) We have developed elements for quasi-optical circuit, for example, quasi-optical antennae, using outputs of our gyrotrons. The elements are used in the scattering measurement system for plasmas.(2) We have constructed the system using our gyrotron as a power source and applied it to the helical system (CHS) of National Institute of Fusion Science and succeeded to observe a spontaneously excited, low frequency drift wave. Less