2D full-wave simulation of waves in space and tokamak plasmas

Abstract

Abstract. Simulation results using a 2D full-wave code (FW2D) for space and NSTX fusion plasmas are presented. The FW2D code solves the cold plasma wave equations using the finite element method. The wave code has been successfully applied to describe low frequency waves in planetary magnetospheres (i.e., dipole geometry) and the results include generation and propagation of externally driven ultra-low frequency waves via mode conversion at Mercury and mode coupling, refraction and reflection of internally driven field-aligned propagating left-handed electromagnetic ion cyclotron (EMIC) waves at Earth. In this paper, global structure of linearly polarized EMIC waves is examined and the result shows such resonant wave modes can be localized near the equatorial plane. We also adopt the FW2D code to tokamak geometry and examine radio frequency (RF) waves in the scape-off layer (SOL) of tokamaks. By adopting the rectangular and limiter boundary, we compare the results with existing AORSA simulations. The FW2D code results for the high harmonic fast wave heating case on NSTX with a rectangular vessel boundary shows excellent agreement with the AORSA code.

Magnetic tilt effect on externally driven electromagnetic ion cyclotron (EMIC) waves

“…The field-aligned Poynting flux is very weak as shown in Figure 2(d) and most wave energy flows perpendicular to B 0 . Here, no clear evidence of the IIH resonance was found, like the previous simulation (Kim et al, 2017).…”

“…The IIH resonance has been examined using a 2D full-wave simulation (FW2D) code at Mercury and Earth. Strong mode conversion occurs at Mercury's magnetosphere in a wide range of L-shell (Kim, Johnson, Valeo, & Phillips, 2015); however, mode-converted IIH wave power at Earth was weaker than at Mercury (Kim et al, 2017). These differences can stem from the physical parameters (such as magnetic field strength or field line length) or simulation conditions (such as initial wave source).…”

“…The code computes the wave power, Poynting flux, and wave absorption when waves are launched from a source location and successfully used for the several tokamak machines (e.g., Shiraiwa et al, 2017, Bertelli et al, 2020 One advantage of using the FEM is that the local basis functions can be readily adapted to boundary shapes and background parameters, such as multiple particle densities, magnetic field configuration, and strength, and provides higher resolution in regions where solutions exhibit singular behavior and mode conversion occurs. For such reasons, various magnetic field topologies (i.e., planetary magnetospheres and tokamaks) have been adopted in the FW2D code (Kim et al, 2016(Kim et al, , 2017Kim, Bertelli, Ono et al, 2019).…”

Electron Inertial Effects on Linearly Polarized Electromagnetic Ion Cyclotron Waves at Earth's Magnetosphere

“…At present, many numerical simulations have been performed to examine wave absorption and mode conversion near the IIH and BB resonances in planetary magnetospheres (e.g., Kim et al, , , , ); however, because the simulation run time is too short for the IIHW to be converted into EIW or the simulation mesh size is larger than the electron inertial scale, the electron inertial effects on wave properties near the IIH and BB resonances have not been fully investigated.…”

Coupled plasma transport and electromagnetic wave simulation of an ECR thruster

“…The instantaneous plasma properties computed in the coarser PIC mesh and the MFAM are smoothed using FIG. 4: Evolution with simulation time of the thrust contributions (see equation (26) in Section §III D) of Xe + (filled diamond), Xe 2+ (diamond), Xe (square), e − (triangle) and the total (solid).…”