HT-7装置软X射线诊断系统及锯齿行为研究

利用HT-7装置上建立的多阵列软X射线诊断系统对等离子体放电中的锯齿不稳定性进行研究，发现锯齿的出现及其行为特点与等离子体电子密度N_e、电子温度T_e、边界安全因子q_α、壁条件等放电参数有密切关系。在低杂波电流驱动等离子体放电条件下，观察到m/n=1/1的中间模振荡出现在锯齿的上升阶段，并迅速发展、饱和、衰减，在锯齿塌陷或先兆振荡出现以前消失。分析和讨论了欧姆加热条件下和低杂波加热条件下的锯齿行为。

Study on sawtooth activities of HT-7 tokamak using soft X-ray diagnostic

Several arrays of soft X-ray diagnostic are developed on the HT-7 tokamak and used to study the sawtooth oscillations. The occurrence and characteristics of the sawtooth are related closely with the discharge conditions such as electron density Ne, electron temperature Te, safety factor qα on the plasma edge, as well as the wall condition, etc. In lower hybrid current drive (LHCD) plasmas, an m/n=1/1 mid-mode oscillation can be observed, which appears during sawtooth ramps, rapidly-develops, saturates, damps and disappears before the sawtooth collapse. The sawtooth behaviors in ohmically heated plasma and LHCD plasma are discussed and summarized.