Progress of gyro-center shift analysis based on the charge exchange in plasmas and the intrinsic rotation of KSTAR

Since the first report of electric field formation on the tokamak edge, Gyro-Ceneter Shift (GCS) analysis based on the ion-neutral charge exchange has explained various phenomena in magnetized plasmas including reversed motion of arc discharge, turbulence suppression of H-mode transition, Bohm diffusions, E-fields of equatorial electro-jet (EEJ) and black aurora[1][2]. GCS analysis can be applied to the solar flare. The origin of intrinsic rotation has been investigated because plasma rotation is a key control parameter for the MHD instabilities. So far, no quantitative agreement is available. Here new analysis of intrinsic rotation is developed based on the electron-ion momentum exchange with the toroidal electric field induced by loop voltage. When the ion-neutral collision frequency is comparable to the electron-ion collision frequency, strong counter-current intrinsic rotation is induced on KSTAR. The comparison of experimental observations on KSTAR and VEST is well agreed with the analysis based on these ion-neutral collisions. The magnitude and time evolution of the intrinsic rotations agrees for the cases with different plasma parameters. It is also found that the impurity concentration is more sensitive to the intrinsic rotation than the neutral density.