Scattered-Field FDTD Algorithm for Hot Anisotropic Plasma With Application to EC Heating

Nowadays, the finite-difference time-domain (FDTD) is accepted as a reliable tool in numerical electromagnetics. In the field of wave propagation in plasmas, the mainstream in theory and applications is oriented to frequency domain asymptotic methods, where the determination of the plasma response presents less difficulty. However, in many cases of interest (like, e.g., mode conversion) this approach breaks down, the solution becomes questionable and therefore a full-wave analysis is necessary. In this work, we present a (novel) scattered-field FDTD algorithm for fully kinetic, anisotropic plasma. As an application, we study the perpendicular electron-cyclotron propagation and absorption in simplified tokamak geometry, under different physics models for the dielectric response of the plasma. In general, since FDTD is a time domain technique, conversion from the frequency domain is needed in order to be able to exploit the existing knowhow on the dielectric response. However, in the case of a constant-frequency wave propagating in a stationary plasma, the FDTD method can be applied directly using the frequency domain dielectric tensor.