Simulating coronal condensation dynamics in 3D

TL;DR

This paper uses 3D magnetohydrodynamic simulations to study coronal rain phenomena, revealing continuous rain formation, plasma blob dynamics, and the influence of magnetic topology and instabilities in a realistic arcade configuration.

Contribution

First 3D simulation of coronal rain in a quadrupolar arcade, incorporating realistic thermodynamics and analyzing instability-driven plasma dynamics.

Findings

Continuous coronal rain develops without large prominence formation.

Plasma blobs form due to thermal instability and follow magnetic field lines.

Rayleigh-Taylor or interchange instability influences plasma descent.

Abstract

We present numerical simulations in 3D settings where coronal rain phenomena take place in a magnetic configuration of a quadrupolar arcade system. Our simulation is a magnetohydrodynamic simulation including anisotropic thermal conduction, optically thin radiative losses, and parametrised heating as main thermodynamical features to construct a realistic arcade configuration from chromospheric to coronal heights. The plasma evaporation from chromospheric and transition region heights eventually causes localised runaway condensation events and we witness the formation of plasma blobs due to thermal instability, that evolve dynamically in the heated arcade part and move gradually downwards due to interchange type dynamics. Unlike earlier 2.5D simulations, in this case there is no large scale prominence formation observed, but a continuous coronal rain develops which shows clear indications of Rayleigh-Taylor or interchange instability, that causes the denser plasma located above the transition region to fall down, as the system moves towards a more stable state. Linear stability analysis is used in the non-linear regime for gaining insight and giving a prediction of the system's evolution. After the plasma blobs descend through interchange, they follow the magnetic field topology more closely in the lower coronal regions, where they are guided by the magnetic dips.