Multilayer mirror soft x-ray spectrometer for fast electron temperature measurement on the compact helical system

Abstract

A multilayer mirror (MLM) soft x-ray spectrometer has been installed on the Compact Helical System. The x-ray energy spectrum from ECH and neutral beam injected heated low beta plasmas was measured as a function of radiation energy. Modulations of the x-ray intensity associated with magnetohydrodynamic instability were observed. The electron temperature measurement was also investigated using the MLM x-ray spectrometer. The data suggest the possibility of a fluctuation measurement of the electron temperature Te with fast time resolution using the MLM spectrometer.