Measurements of hard X-ray emission profiles in the TCV Tokamak during electron cyclotron heating and current drive

A multichannel hard X-ray (HXR) diagnostic system developed for the Tore Supra tokamak has been employed on the TCV tokamak with the aim of characterising the spectral and spatial distribution of fast-electron Bremsstrahlung emission during electron cyclotron heating (ECH) and current drive (ECCD). The ECH and ECCD experiments described in this paper have been carried out with up to three 0.5 MW gyrotrons, operating in X-mode at the second harmonic (82.7 GHz). The launching mirrors can be independently rotated in both the poloidal and the toroidal direction, providing great flexibility in the choice of heating locations and parallel wave numbers. The HXR camera constitutes a crucial tool for investigating the location of the power deposition and the distribution and dynamics of suprathermal electrons. Initial results are presented in this paper. (authors)