Synergistic Influences of Kinetic Effects from Thermal Particles and Fast Ions on Internal Kink Mode

The kinetic effects of thermal particles and fast ions on internal kink (IK) mode are numerically investigated by the MHD-kinetic hybrid code MARS-K. It is shown that either thermal particles or fast ions have stabilizing influence on IK. However, the former can not fully stabilize IK, and the later can suppress the IK. In addition, the synergistic effect from thermal particles and fast ions induces more stronger damping on IK. The kinetic effects from particles significantly raise the critical value of poloidal beta (\beta_\rm p^\rm crit) for driving IK in the toroidal plasma. This implies a method of controlling IK or sawtooth in the high-\beta_\rm p discharge scenario of tokamak. It is noted that, at the q=1 rational surface, mode structure becomes more sharp due to the self-consistent modification by particles' kinetic effect.