Studies of high power oscillation source with frequency tunability in the millimeter and sub-millimeter waves

聚变堆前级回旋管的输出功率和脉冲宽度分别为0.5 mW和100s或0.2 mW和550s，频率范围为0.17太赫兹。然而，即使输出功率有所下降，学术研究和工业应用也需要使用连续波回旋管。为了达到这个目的，抑制回旋管内部过热以及限制其脉冲宽度的不稳定性所产生的气体是必不可少的。本研究在2006年的振荡实验中对用于聚变研究的0.17T回旋管的参数进行了优化。结果表明，回旋管在长脉冲工作时，真空压力稳定在L×10-8Torr的低水平，实现了0.6 mW的输出功率、46%的效率和1h(3600s)的运行，1 mW-800s-55%和0.8 mW-2000s-57%的演示是成功的，实现了高功率、高效率和稳定运行。结果表明，回旋管的总输出能量超过150GJ，具有很高的可靠性。作为回旋管频率稳定性的启动，还进行了7T-SCM的高速磁场扫描实验。检查02T/5S的扫频。从而完成了快速频率可调谐实验的准备工作，并展望了高频可调谐回旋管的研究前景。

The output power and pulse duration of previous gyrotron for fusion reactor were 0.5MW and 100s or 0.2MWand 550s in the frequency range of 0.17 THz, respectively. However, a continuous-wave gyrotron is required for academic research and industrial application even if some output power decreased. For this purpose, suppression of outgases due to overheating inside the gyrotron and instabilities, which limit the pulse duration of the gyrotron, is indispensable.In this study, the parameters of the 0.17T gyrotron for fusion research, which is modified in a mode converter, an electron gun and control circuit, are optimized in the oscillation experiment in 2006. As a result, demonstration of 0.6MW output power, 46% efficiency and 1 hour (3600s) operation were carried out because the vacuum pressure in the gyrotron was stabilized in the low level of l×10-8 torr in the long pulse operation.Furthermore, the demonstrations of 1MW-800s-55% and 0.8MW-2000s-57% were successful and high power, high efficiency and steady state operation were also accomplished. This result shows the high reliability of the gyrotron because total output energy exceed more than 150GJ.High-speed sweep experiment of magnetic field of 7T-SCM for gyrotron oscillation was also carried out as a start-up of frequency tenability of the gyrotron. The sweep rate of 02T/5s was checked. As a result, the preparation of the experiment for the fast frequency tunability has been accomplished and an outlook for research to high frequency and tunability gyrotron has been also obtained.