Recent ECRH/ECCD experiments aiming for higher density and temperature operations in the LHD

Abstract

In LHD, real-time control of the incident EC wave polarization and quick response microwave bolometer for monitoring the stray radiations have been developed for efficient and safe operation of the high power and long pulse ECRH/ECCD. As a high power ECRH/ECCD application aiming for high density, ECRH has been demonstrated up to 85% of the cutoff density by the fundamental X-mode excitation in HFS with use of a horizontal port antenna located in LFS. As another application aiming for high temperature, the effect of the control of the rotational transform with use of the ECCD on the sustainment of the e-ITB is investigated. It has been suggested that higher local electron energy confinement time is obtained inside the e-ITB with placing the m/n = 2/1 magnetic island near the edge of the e-ITB compared to the case when the 2/1 island is vanished in the plasma.