Global particle simulation of lower hybrid wave propagation and mode conversion in tokamaks

Abstract

Abstract. Particle-in-cell simulation of lower hybrid (LH) waves in core plasmas is presented with a realistic electron-toion mass ratio in toroidal geometry. Due to the fact that LH waves mainly interact with electrons to drive the current, ion dynamic is described by cold fluid equations for simplicity, while electron dynamic is described by drift kinetic equations. This model could be considered as a new method to study LH waves in tokamak plasmas, which has advantages in nonlinear simulations. The mode conversion between slow and fast waves is observed in the simulation when the accessibility condition is not satisfied, which is consistent with the theory. The poloidal spectrum upshift and broadening effects are observed during LH wave propagation in the toroidal geometry.

Kinetic particle simulations in a global toroidal geometry

“…Another widely used and successful tool, the gyrokinetic toroidal code (GTC) has undergone continuous development for the past two decades and has been applied to the study of plasma transport in the core region 17 . GTC is a well-benchmarked, first-principles code which has been extensively applied to the investigation of neoclassical transport 18,19 , microturbulence [20][21][22][23][24][25] , mesoscale Alfvén eigenmodes [25][26][27] excited by energetic particles, macroscopic MHD modes [28][29][30] (kink and tearing modes) and radio frequency (RF) waves [31][32][33][34][35][36][37] in the core region. However, the assumptions used in studying turbulence in the core region may not be valid in the SOL region.…”