Simulation Study on the Motion of the Pressure Perturbation in an Axisymmetric Toroidal System

Abstract

In tokamaks, it is observed that an ablated and ionized pellet moves toward the low field side of the torus. This phenomenon can be considered as the magnetohydrodynamic (MHD) wave propagation in the 1/ R varying toroidal field because the pressure perturbation is induced by injecting a pellet, where R is the major radius of tokamaks. The dominant mechanism which causes this displacement is revealed, by solving nonlinear MHD equations numerically, as the multi-dimensional nonlinear fast magnetosonic wave propagation in a toroidal magnetic field. Linear wave propagation does not work for this displacement. The nonlinearity is clarified by successive approximation.