Measurements of radial profiles of the ion temperature and the plasma rotation velocity with the TFTR vertical x‐ray crystal spectrometer

The TFTR vertical x‐ray crystal spectrometer has now been operating with three crystals and position‐sensitive detectors according to the original design specifications. The observed spectra of heliumlike Ti xxi, Cr xxiii, Fe xxv, and Ni xxvii have permitted a detailed comparison with the predictions from atomic theories, and they have provided data on the radial profiles of the ion temperature and toroidal rotation velocity, as well as the radial ion charge‐state distribution in TFTR discharges. Central ion temperatures of 20 keV and central plasma rotation velocities of 5×105 m/s have been recorded from plasmas with auxiliary neutral beam heating. These experimental results are presented. Also discussed are further instrumental improvements, such as the installation of two additional crystals and detectors and the installation of γ and neutron shielding, which will make it possible to measure under full DD and DT operation with 27 MW of neutral beam injection where neutron production rates of 1019 neutr...