Verification of nonlinear particle simulation of radio frequency waves in tokamak

TL;DR

This paper develops and verifies a nonlinear simulation model for RF waves in tokamak plasmas, capturing key phenomena like wave trapping, decay instability, and ion heating, advancing understanding of plasma wave dynamics in fusion devices.

Contribution

It introduces a fully kinetic ion and drift kinetic electron model with Boris push in Boozer coordinates, and verifies nonlinear wave phenomena in tokamak-relevant conditions.

Findings

Verification of linear dispersion relation for RF waves

Observation of parametric decay instability

Identification of ion perpendicular heating due to ICQM

Abstract

Nonlinear simulation model for radio frequency (RF) waves in fusion plasmas has been developed and verified using fully kinetic ion and drift kinetic electron. Ion cyclotron motion in the toroidal geometry is implemented using Boris push in the Boozer coordinates. Linear dispersion relation and nonlinear particle trapping are verified for the lower hybrid (LH) wave and ion Bernstein wave (IBW). Parametric decay instability is observed where a large amplitude pump wave decays into an IBW sideband and an ion cyclotron quasimode (ICQM). The ICQM induces an ion perpendicular heating with a heating rate proportional to the pump wave intensity.