Investigating ICRF Core Physics with a Hybrid Method using δf Particles

Abstract

Particle‐in‐cell simulations of ICRF core physics yield a significant amount of noise that can overwhelm the low amplitude signals associated with ICRH. To overcome this noise, we employ a hybrid approach that uses a fluid model for electrons and the delta‐f particle‐in‐cell (DFPIC) method for ions. Noise is reduced to a level well below the amplitude of the signal and time steps are permitted to go beyond the electron time scales. With this formulation we have explored minority heating scenarios in Alcator C‐Mod and high harmonic heating scenarios in NSTX. We can also employ the fluid model for both electrons and ions to investigate cold plasma scenarios. Here we examine ion test particles with particular attention paid to particle paths near resonance layers. We present our technique for investigating full particle orbits from a single toroidal mode expansion.