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.
Highlights
In the solar system, many planets including Mercury, Earth, Jupiter, Saturn, Uranus, and Neptune, and their moons are magnetized
It is found that (a) linearly polarized ElectroMagnetic Ion Cyclotron (EMIC) waves generated via mode conversion are localized near the magnetic equator; (2) FW2D and AORSA results show an excellent agreement in the rectangular boundary; and (3) FW2D results with a realistic limiter boundary are significantly different to results with the rectangular vessel boundary
Recent experimental studies of high harmonic fast wave (HHFW) heating on the National Spherical Torus eXperiment (NSTX) [31] have demonstrated that up to 60% of the coupled HHFW power can be lost in the scape-off layer (SOL) [15,16]
Summary
Many planets including Mercury, Earth, Jupiter, Saturn, Uranus, and Neptune, and their moons are magnetized. ULF waves can lead to significant acceleration, transport, and loss of electrons during magnetic storms [1] They can be a source for plasma transport at the magnetopause and have been shown to be responsible for ion outflows [2,3]. EMIC waves are considered to be a dominant radiation belt loss mechanism leading to rapid pitch angle scattering radiation belt electrons of almost all energies on the time-scale of seconds with subsequent loss to the ionosphere [4] These waves have been used as a diagnostic tool to measure plasma densities [5,6]. It is found that (a) linearly polarized EMIC waves generated via mode conversion are localized near the magnetic equator; (2) FW2D and AORSA results show an excellent agreement in the rectangular boundary; and (3) FW2D results with a realistic limiter boundary are significantly different to results with the rectangular vessel boundary
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