Solar prominences: 'double, double ... boil and bubble'

TL;DR

This paper presents detailed magnetohydrodynamic simulations of solar prominences, revealing complex bubbling and mixing processes driven by Rayleigh-Taylor instabilities, which align well with observed phenomena.

Contribution

The study provides the first true macroscopic MHD simulations of prominence bubbling, demonstrating non-linear convective motions and mixing mechanisms consistent with observations.

Findings

Simulations show hot bubbles and falling pillars interacting dynamically.

Rayleigh-Taylor fingers impact transition region plasma, promoting mixing.

Synthetic EUV views match observed prominence features.

Abstract

Observations revealed rich dynamics within prominences, the cool 10,000 K, macroscopic (sizes of order 100 Mm) "clouds" in the million degree solar corona. Even quiescent prominences are continuously perturbed by hot, rising bubbles. Since prominence matter is hundredfold denser than coronal plasma, this bubbling is related to Rayleigh-Taylor instabilities. Here we report on true macroscopic simulations well into this bubbling phase, adopting a magnetohydrodynamic description from chromospheric layers up to 30 Mm height. Our virtual prominences rapidly establish fully non-linear (magneto)convective motions where hot bubbles interplay with falling pillars, with dynamical details including upwelling pillars forming within bubbles. Our simulations show impacting Rayleigh-Taylor fingers reflecting on transition region plasma, ensuring that cool, dense chromospheric material gets mixed with prominence matter up to very large heights. This offers an explanation for the return mass cycle mystery for prominence material. Synthetic views at extreme ultraviolet wavelengths show remarkable agreement with observations, with clear indications of shear-flow induced fragmentations.