Two-Dimensional Axisymmetric Finite Element Simulation of Lower Hybrid Wave with an Iterative Scheme

Abstract

Simulating waves in hot plasmas in configuration space is a difficult problem because of the non-local property of the plasma response, which makes the wave equation an integro-differential one. In this research, we conducted an axisymmetric hot plasma full wave simulation at the lower hybrid frequency range with the finite element method. Kinetic effects were introduced in the direction parallel to the magnetic field. We implemented the code so that it can handle an arbitrary velocity distribution function to introduce electron kinetics. An iterative method was utilized to introduce the non-local hot plasma contribution, which is more memory efficient than direct solving. The hot plasma perturbed current density was iteratively calculated in our scheme. For the present simulation, we used the plasma equilibrium obtained by the experiment with the TST-2 spherical tokamak, which is located at the University of Tokyo. The simulation with the realistic profiles successfully converged. The electron heating power deposition profile was estimated for the obtained electric field solutions.