Neutral particle analyzer with feedback control system on HT-7 tokamak

A neutral particle analyzer (NPA) employing a scanning mode and feedback control technique was developed and installed on the HT-7 tokamak. A horizontal view is used to measure ion temperature profiles. The spatial resolution is about 2 cm shot-by-shot. The performance of analyzer is improved greatly by employing feedback control system. The constructing of analyzer, data acquisition and the technique of feedback control are described. Preliminary measurement results in ohmic heated plasmas and lower-hybrid current drive plasmas are presented and simulated by Monte-Carlo code.