Multi-Fluid Simulations of Collisional Plasma Instabilities in the Solar Chromosphere

Abstract:

The state-of-the-art instruments (IRIS–ALMA–DKIST) are challenging our understanding of the thermodynamics of the solar chromosphere. The chromosphere is the region between the solar surface and the million–degree corona. Chromospheric physics involves complex processes that are not well-described by the standard MHD assumptions, such as partially ionized regions, diffusive terms becoming non-negligible compared to collisional effects, and ion species which transition between magnetized and demagnetized. All these ingredients are necessary to develop thermal and Farley-Buneman instabilities in the solar chromosphere. By using the new multi-fluid multi-species (MFMS) code Ebysus, we work to simulate the effects of thermal and Farley-Buneman instabilities in the solar chromosphere. Ebysus models each ion species and ionization level as a separate fluid and tracks many fluids at once, making it well-suited to investigate these instabilities with a fluid-model. This paper will describe these instabilities as they appear in the solar chromosphere using Ebysus and making comparisons to PIC code simulations.

This work is supported by NSF Grant 1903416.