3D numerical simulations of oscillations in solar prominences

Abstract

Context. 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, however. Aims. We numerically investigate the periodicity and damping of transverse and longitudinal oscillations in a 3D model of a curtain-shaped prominence. Methods. 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 (wx) and density (ρp0) of the prominence, and the magnetic field strength (B) of the solar corona. We studied the periodicity and attenuation of the induced oscillations. Results. We found that longitudinal oscillations can be fit with the pendulum model, whose restoring force is the fieldaligned 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 ρp0, but there are no variations with B. The attenuation of transverse oscillations was investigated by analysing the velocity distribution and computing the Alfvén continuum modes. We conclude that resonant absorption is the mean cause. Damping of longitudinal oscillations is due to some kind of shear numerical viscosity. Conclusions. Our model is a good approximation of a prominence body that nearly reproduces the observed oscillations. However, more realistic simulations that include other terms such as non-adiabatic processes or partially ionised plasmas are necessary to obtain better results.

Transverse oscillations of a double-structured solar filament

“…4. However, it differs from sinusoidal variations of the parameters shown in Zhou et al (2018), Adrover-González & Terradas (2020. This difference appears to be caused by the different structure of the filament.…”

Does a solar filament barb always correspond to a prominence foot?

“…Once perturbed by external disturbances, the threads inside a filament would be pushed aside from the equilibrium positions, and then start to oscillate under the restoring force. Filament oscillations can be classified into transverse oscillations and longitudinal oscillations (Arregui et al 2018), depending on whether the perturbation is perpendicular or parallel to the local magnetic field (Zhou et al 2018;Zhang et al 2019;Adrover-González & Terradas 2020). The two modes may coexist in one event (Wang et al 2016;Zhang et al 2017;Mazumder et al 2020).…”

Oscillations and mass-draining that lead to a sympathetic eruption of a quiescent filament

“…A simulation shows that mass drainage reduces the damping time considerably in one strong perturbation (Zhang et al 2013). Recent numerical simulations have shed light on the nature of large-amplitude longitudinal oscillations (e.g., Terradas et al 2015;Zhou et al 2018;Adrover-González & Terradas 2020;Liakh et al 2020Liakh et al , 2021.…”