Bifurcation and Relaxation of Radial Electric Field in Enhanced Reversed Shear Tokamak Plasmas

Abstract
It is shown that toroidal magnetic field ripple induced thermal and fast ion loss can drive the radial electric field to bifurcate over the local maximum of the parallel (or poloidal) viscosity. The subsequent plasma profile evolution reduces the hot particle density and relaxes the radial electric field. This behavior is consistent with the experimental observations in enhanced reversed shear mode in tokamaks.