Forming prominences accounting for partial ionisation effects

TL;DR

This paper investigates how partial ionisation influences prominence formation and evolution in the solar atmosphere using a two-fluid model, revealing significant effects on shock dynamics and plasma decoupling.

Contribution

It is the first study to model prominence formation in a two-fluid plasma setting, highlighting the impact of partial ionisation on prominence dynamics.

Findings

Pronounced two-fluid effects in shocks during condensation.

Decoupling effects in the prominence-corona transition region (~100 m/s).

Differences in evolution post-formation due to plasma-neutral interactions.

Abstract

One of the most striking structures in the solar atmosphere are prominences, predominantly coronal structures, with thermodynamic conditions that vary from chromospheric internally to the corona that surrounds them. These structures play an important role in the energy transfer between all layers of the atmosphere. Although mostly studied as a fully ionised plasma, prominences are, in fact, composed of partially ionised plasma. We do not yet fully understand the extent to which the two-fluid plasma-neutral properties play a role in the evolution of these coronal structures. In this work, we explore for the very first time how prominence formation and growth in a coronal loop evolves in a two-fluid setting. We used MPI-AMRVAC to study the evaporation-condensation process, where we consider radiative cooling, thermal conduction, and localised heating in a coronal loop in a fully stratified atmosphere. We report on the differences the two-fluid plasma brings into the prominence evolution, and more specifically in the period after the dynamic formation process finishes. Furthermore, we highlight the role it plays during the linear and the non-linear phases of the evolution. We find pronounced two-fluid effects in shocks that appear with the first complete condensation and confirm decoupling effects in the PCTR on the order of 100$\,$m$\,$s$^{-1}$, consistent with observations.