3D numerical simulations of oscillations in solar prominences

TL;DR

This study uses 3D numerical simulations to analyze the periodicity and damping mechanisms of transverse and longitudinal oscillations in solar prominences, revealing different driving forces and damping processes.

Contribution

It provides a comprehensive 3D MHD simulation analysis of prominence oscillations, identifying key factors influencing period and damping mechanisms.

Findings

Longitudinal oscillation periods fit the pendulum model.

Transverse oscillation periods increase with prominence density and width.

Resonant absorption causes damping of transverse oscillations.

Abstract

Oscillations in solar prominences are a frequent phenomenon, and they have been the subject of many studies. A full understanding of the mechanisms that drive them and their attenuation has not been reached yet. We numerically investigate the periodicity and damping of transverse and longitudinal oscillations in a 3D model of a curtain-shaped prominence. We carried out a set of numerical simulations of vertical, transverse and longitudinal oscillations with the high-order finite-difference Pencil Code. We solved the ideal magnetohydrodynamic (MHD) equations for a wide range of parameters, including the width and density of the prominence, and the magnetic field strength (B) of the solar corona. We studied the periodicity and attenuation of the induced oscillations. We found that longitudinal oscillations can be fit with the pendulum model, whose restoring force is the field aligned component of gravity, but other mechanisms such as pressure gradients may contribute to the movement. On the other hand, transverse oscillations are subject to magnetic forces. The analysis of the parametric survey shows, in agreement with observational studies, that the oscillation period (P) increases with the prominence width. For transverse oscillations we obtained that P increases with density and decreases with B. For longitudinal oscillations we also found that P increases with density, but there are no variations with B. The attenuation of transverse oscillations was investigated by analysing the velocity distribution and computing the Alfv\'en continuum modes. We conclude that resonant absorption is the mean cause. Damping of longitudinal oscillations is due to some kind of shear numerical viscosity.