Measurements of ion temperature and flow velocity using symmetric and asymmetric double probes in the boundary plasma of the JFT-2M tokamak

Abstract

The radial profiles of the ion temperature as well as the flow velocity have been measured by using rotatable symmetric and asymmetric double probes in the boundary plasma of the JFT-2M tokamak. It has been found that the ion temperature is higher than the electron temperature by a factor of about 10, and the flow velocity is 0.2-0.3 of the ion sound velocity in the SOL for both ohmic and NB injection heating. These data can help to determine the cross-field thermal diffusivity in tokamak boundary plasma.