Recovering the Damping Rates of Cyclotron Damped Plasma Waves from Simulation Data

Abstract

Plasma waves with frequencies close to the particular gyrofrequencies of the charged particles in the plasma lose energy due to cyclotron damping. We briefly discuss the gyro-resonance of low frequency plasma waves and ions particularly with regard to particle-in-cell (PiC) simulations. A setup is outlined which uses artificially excited waves in the damped regime of the wave mode's dispersion relation to track the damping of the wave's electromagnetic fields. Extracting the damping rate directly from the field data in real or Fourier space is an intricate and non-trivial task. We therefore present a simple method of obtaining the damping rate Γ from the simulation data. This method is described in detail, focusing on a step-by-step explanation of the course of actions. In a first application to a test simulation we find that the damping rates obtained from this simulation generally are in good agreement with theoretical predictions. We then compare the results of one-, two-and three-dimensional simulation setups and simulations with different physical parameter sets.

A Tractable Estimate for the Dissipation Range Onset Wavenumber Throughout the Heliosphere

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Analytical treatment of particle motion in circularly polarized slab-mode wave fields

“…The ACRONYM PiC code (Kilian et al 2012), which serves as the basis for the magnetostatic code used in this work, has been thoroughly tested over the years. During the process new test cases have been established, such as the analysis of wave modes (Kilian et al 2017) and their damping characteristics (Schreiner et al 2017b), which can be used to check for inconsistencies in the interplay of particle motion and electromagnetic fields.…”

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