Time-domain simulation of nonlinear radiofrequency phenomena

Abstract

Nonlinear effects associated with the physics of radiofrequency wave propagation through a plasma are investigated numerically in the time domain, using both fluid and particle-in-cell (PIC) methods. We find favorable comparisons between parametric decay instability scenarios observed on the Alcator C-MOD experiment [J. C. Rost, M. Porkolab, and R. L. Boivin, Phys. Plasmas 9, 1262] and PIC models. The capability of fluid models to capture important nonlinear effects characteristic of wave-plasma interaction (frequency doubling, cyclotron resonant absorption) is also demonstrated.

Benchmark of a parallel fluid code for parametric decay instability in inhomogeneous plasmas

“…Furthermore, at the upper hybrid resonance layer of the wave heating of electron cyclotron wave in Tokamak plasma, there are still a few PDIs arising. And if we consider the kinetic linear mode conversion, of which the UHW is converted into electron Bernstein wave, we believe that the PDIs will become richer [9]. …”

“…Under the scheme of fluid model, there are a few possible decay channels near the upper-hybrid layer. First of all, the produced UHW will decay into a low hybrid wave (LHW) and a sideband UHW [9] , called upper-hybrid decay instability (UDI); secondly, the electron cycle wave decays into a LHW and an electromagnetic sideband wave, sometimes this channel is called Raman Scattering of magnetized plasma; thirdly, the electron cyclotron wave decays into LHW and UHW directly. The schematic of the simulation setup is shown in Fig.…”

“…But there still some deficiencies exist for the large scale space problem. In recent, the authors supplied some PDIs results of ion Bernstein wave with the method of the coupled Maxwell and plasma equations in full space-time domain [9], the results indicate that, the full space-time domain simulation can offer all of linear and nonlinear physics processes and all of frequency and wave vector components. Comparing to the other methods, the full space-time domain simulation has its own advantages for the study of the PDI.…”

“…During the past four decades, PDIs have already been developed deeply in experiments and theories [1][2][3][4][5][6][7][8][9][10][11]. But there still some deficiencies exist for the large scale space problem.…”

Nonlinear particle simulation of ion cyclotron waves in toroidal geometry

“…To address these crucial nonlinear physics we have developed a toroidal PIC simulation model based on the initial value approach [3][4]. Nonlinear phenomena of the RF waves have been studied in the slab geometries with particle codes such as GeFi [5] and Vorpal [6].…”