Lower hybrid dynamics by ECE spectra in Tore Supra

The suprathermal electron cyclotron radiation is used to investigate fundam ental phenomena governing electron tail formation during lower hybrid curre nt drive (LHCD). To this end, an approximate analytical solution of the 2-D time-dependent Fokker-Planck equation is developed. Electron cyclotron emi ssion (ECE) is analysed with this model. The pitch-angle scattering time, t he characteristic time of the quasi-linear diffusion process, the perpendic ular temperature and the quasi-linear diffusion coefficient are measured by fitting the temporal evolution of the ECE si,signal. (C) 2001 Elsevier Sci ence B.V. All rights reserved.