Escaping ion measurement with high time resolution during bursting modes induced by neutral beam injection on CHS

CHSにおける中性粒子ビーム誘因バーストモード中の高時間分解能損失イオン計測

篠原 孝司; 磯部 光孝*; Darrow, D. S.*; 清水 昭博*; 永岡 賢一*; 岡村 昇一*

Shinohara, Koji; Isobe, Mitsutaka*; Darrow, D. S.*; Shimizu, Akihiro*; Nagaoka, Kenichi*; Okamura, Shoichi*

A scintillator-based lost ion probe can measure the temporal evolution of both the gyro-radius and the pitch angle of energetic ions escaping a magnetically-confined plasma. On this system, the time resolution of the detailed two-dimensional (2D) measurement is determined by a framing rate of the video camera that records the luminous images produced by the ions striking the scintillator plate. By installing an image-intensified high-speed video camera system, the temporal resolution was improved from about 33 ms to 0.07 ms. We have successfully captured some new fast features caused by bursting modes, whose time scale is a few milli-second, induced by a neutral beam injection.