Simulation of High Ion Temperature Mode in JT-60

Abstract

The high ion temperature mode in JT-60, where T_i above 10 keV were obtained by hydrogen beam heating of 20 MW into hydrogen limiter plasmas with I_p=1∼2 MA, is investigated by using the one dimensional transport code and experimental data of electron density and temperature. It is found that, in a low density plasma with high Z_eff, the dilution of thermal ions due to impurities and fast ions produced by neutral beam injection causes rapid increase in the ion temperature. On the other hand, in the steady state, the dilution has little effect on the central ion temperature for fixed electron temperature because the convection loss is dominant.