Modeling multiphase plasma in the corona: prominences and rain

TL;DR

This paper reviews advances in modeling multiphase coronal plasma, explaining how cool prominences and rain form through thermal instability driven by coronal heating and magnetic effects.

Contribution

It synthesizes current models of prominence and rain formation, highlighting the shared physical mechanisms and identifying future challenges in understanding their detailed structures.

Findings

Thermal instability triggers condensations in the corona.

Models show morphology reveals heating mechanisms.

Multiple pathways lead to linear instability.

Abstract

We review major achievements in our understanding of multiphase coronal plasma, where cool-dense and hot-tenuous matter coexists, brought about by advances in modeling and theory, inspired by observations. We give an overview of models that self-consistently form solar (or stellar) prominences and filaments, or (postflare) coronal rain, and clarify how these different phenomena share a common physical origin, relating radiative losses and coronal heating. While we do not fully understand the coronal heating, multi-dimensional models of solar prominence and rain formation demonstrate how thermal instability triggers condensations, and how their morphology may reveal aspects of the applied heating at play. We emphasize how the many pathways to linear instability due to combined ingredients of heat-loss, gravity, flows, and magnetic topologies are all involved in the resulting nonlinear magnetohydrodynamics. We provide some challenges to future model efforts, especially concerning prominence fine structure, internal dynamics, and their overall lifecycle.