Solar prominences embedded in flux ropes: morphological features and dynamics from 3D MHD simulations

TL;DR

This study uses 3D MHD simulations to explore the morphology and dynamics of solar prominences within flux ropes, revealing oscillation damping, instability triggers, and the influence of magnetic orientation on structure formation.

Contribution

It provides new insights into prominence behavior in flux ropes, including oscillation damping mechanisms and the suppression of certain instabilities due to magnetic orientation.

Findings

Vertical oscillations are strongly attenuated by continuum damping.

Kelvin-Helmholtz instability can be triggered by nonlinearity.

Magnetic orientation prevents Rayleigh-Taylor instabilities.

Abstract

The temporal evolution of a solar prominence inserted in a three-dimensional magnetic flux rope is investigated numerically. Using the model of Titov Demoulin (1999) under the regime of weak twist, the cold and dense prominence counteracts gravity by modifying the initially force-free magnetic configuration. In some cases a quasi-stationary situation is achieved after the relaxation phase, characterized by the excitation of standing vertical oscillations. These oscillations show a strong attenuation with time produced by the mechanism of continuum damping due to the inhomogeneous transition between the prominence and solar corona. The characteristic period of the vertical oscillations does not depend strongly on the twist of the flux rope. Nonlinearity is the responsible for triggering the Kelvin-Helmholtz instability associated to the vertical oscillations and that eventually produces horizontal structures. Contrary to other configurations in which the longitudinal axis of the prominence is permeated by a perpendicular magnetic field, like in unsheared arcades, the orientation of the prominence along the flux rope axis prevents the development of Rayleigh-Taylor instabilities and therefore the appearance of vertical structuring along this axis.