The carbon impurity particle transport in ohmic discharges on the HT-7 tokamak

The line-integrated optical measurement of impurity radiation profiles for the study of light impurity transport is performed in the HT-7 tokamak. The carbon impurity line emissivity is obtained by Abel inversion. The radial transport behaviours of carbon impurities at different central line averaged electron densities n(e), are investigated in ohmic discharges. The diffusion coefficient D-k(r), the convection velocity W-k(r) and the total flux of the impurity ions Gamma(k) decrease with the increase of n(e), which shows a reduction in the impurity particle transport at higher electron densities.