Global Gyrokinetic Simulation of Linear Micro-Instability Using Parameters Referring to HL-2A Plasma with Ion Transport Barrier

抄録

We study linear micro-instabilities using parameters referring to HL-2A plasma with ion Internal Transport Barrier (ITB) by means of the global toroidal gyrokinetic code GKNET including kinetic electron dynamics. It is found that a type of drift mode, which real frequency is low and changes the sign from electron diamagnetic direction to that of ion continuously as the poloidal wavenumber increases, dominates plasmas with peaked density profile while with relatively flat ion/electron temperature profiles. The instability is found to be sensitive to the perpendicular electron temperature T_e⊥, similar to the standard trapped electron mode, which is consistent with the observation of ion-ITB collapse after ECRH in the HL-2A experiment.