Observation of suprathermal ions in the TCV during ECH and ECCD

1. Experimental setup. These experiments on the TCV Tokamak (R=0.88 m, a=0.25 m, Ip < 1 MA, BT < 1.54 T) em ployed the X2 (82.7 GHz) EC system , with a total delivered power of up to 2.4 MW in X-mode, for a wide variety of plasma shapes and a broad range of heating locations. The central electron density was 1-2·10 19 m -3 , the electron temperature reached 7 keV at full X2 EC power, the plasma elongation was 1.15-1.6 and the triangularity –0.3-+0.3. Modulation of the EC power was used to study the dynamics of the fast particle population (Fig.1). A 5-channel Neutral Particle Analyzer [9] with electrostatic discrimination on TCV views the plasma centre along a vertical chord. The NPA voltage sweeps the energy channels to measure neutral particle energies in the energy range of (0.6›6.5 keV), with a time resolution of 13 ms. A 14 vertical channel FIR interferometer is used to m easure the electron density profile. Plasma electron temperature profiles were derived from the soft X-ray radiation spectrum measurements (XTemeasurements). The high energy electron population created by ECCD is diagnosed primarily with a hard X-ray (HXR) pinhole camera (on loan from Tore Supra) and with a high field side electron cyclotron emission (ECE) system. The EC power deposition and current drive profiles (Fig.2) are calculated by the TORAY ray-tracing code with magnetic equilibrium reconstruction from the LIUQE code and Thomson scattering electron temperature and density profiles.