Tungsten accumulation in H-mode plasmas of JT-60U

Abstract

It has been observed that with increasing toroidal rotation velocity inside the q = 1 layer in the direction opposite to the plasma current, sawtooth activity becomes moderate and tungsten accumulation becomes significant. The tungsten accumulation level is significantly reduced from this trend in the case when electron cyclotron wave or high energy neutral beam is injected into the plasma core. In contrast, the tungsten accumulation is kept high by the electron cyclotron wave injection into the peripheral region.