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

回旋管是一种覆盖毫米和亚毫米波长范围的高功率源。我们正在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。亚毫米波段回旋管的研制我们研制了一台8-12T超导磁体，该磁体是为回旋管而优化的，并设计了一个电子枪和一个圆柱腔来构成回旋管。对根据设计制作的回旋管进行了测试，得到了以下结果：(1)一种新型的谐振式回旋管产生了亚毫米波，输出功率为二次谐振处。其最大频率为404 GHz(对应波长为0.75 mm)，功率为几千瓦。悉尼大学的回旋管IVA已经实现了高达516 GHz的高频工作，这是稳定回旋管的世界纪录。这项工作是在我们团队的合作下完成的。(2)回旋加速器的谐波操作Up…在高频回旋管所必需的354 GHz处(腔模式)，观察到了更多到3。在354 GHz(对应波长为0.85 mm)的二次谐波下，我们成功地实现了高功率(-3.3kW)的高频(-140 GHz)脉冲输出。该运算用于等离子体的散射测量。(4)计算机模拟结果显示了基频和二次谐波运算之间的模式竞争。用我们的亚毫米波伽玛管证实了这一结果。我们找到了高频回旋管作为亚毫米波光源所必需的单模工作在二次谐波的条件。亚毫米波回旋管在等离子体散射测量中的应用(1)我们利用回旋管的输出研制了用于准光学电路的元件，例如准光天线。利用我们的回旋管作为电源，搭建了该系统，并将其应用于美国国家核聚变科学研究所的螺旋系统，成功地观测到了自发激发的低频漂移波。较少

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