Investigation of high energy electrons in lower hybrid current drive plasma with electron cyclotron emission measurement in the WT-3 tokamak

Abstract

Electron cyclotron emission (ECE) from lower hybrid current drive plasma in the WT-3 tokamak has been measured along a vertical chord where the magnitude of the toroidal field is constant. From the frequency of the peak of the down-shifted second harmonic X-mode emission, the perpendicular temperature is evaluated to be about 50, 40 and 25 keV for plasmas with a current of 65, 50 and 24 kA, respectively. Also, the line integrated tail electron density is evaluated from the peak intensity for these plasmas and found to be 1.7, 0.9 and 0.5 × 1012 cm−2, respectively. It is found that the perpendicular temperature is an increasing function of the component of the momentum parallel to the plasma current, p1 , and that the gradient of the perpendicular temperature along p1 increases as the plasma current decreases.