SPECTROSCOPIC MEASUREMENTS OF THE ION TEMPERATURE IN FRONT OF A TOKAMAK LIMITER

In the beam heated (1.3 MW) plasma of the TEXTOR tokamak, ion temperat ures T-i between 30 and 120 eV have been measured in front of a test l imiter at line averaged electron densities between 4 x 10(13) and 1.5 x 10(13) cm(-3). The Doppler broadened profile of the C VI line lambda = 529 nm, excited by charge exchange with recycling hydrogen (deuteri um) atoms, was used for the T-i determination. Errors introduced by fi nite energy equipartition times between C6+ and D+ ions, by correction for fine structure and the Paschen-Back effect, and by possible blend ing with an O VI line, are discussed. Profile distortion by superposit ion of molecular D-2 lines was considerably reduced by observation wit h a high resolution spectrometer (lambda/Delta lambda > 5 x 10(4)). Es timates of D-2 particle energies and the C6+ poloidal rotation velocit y have been performed.