Characteristics of ICRF loading during the H-mode in the JFT-2M tokamak

Abstract

H-mode plasmas have been observed during ICRF heating in JFT-2M. In H-mode plasmas, there is a remarkable difference in the antenna loading between single-null divertor discharges and limiter discharges. When an L-H transition occurs, the loading resistance tends to decrease in single-null divertor plasmas but it increases strongly in limiter plasmas. It is shown that the difference in the behaviour of the loading resistance can be attributed to the change of the density profile; also, the antenna loading is strongly affected by the size of the antenna-plasma distance.