On the robustness of the pendulum model for large-amplitude longitudinal oscillations in prominences

TL;DR

This study validates the pendulum model as a robust explanation for large-amplitude longitudinal oscillations in solar prominences, demonstrating its effectiveness even with weak magnetic fields through numerical simulations.

Contribution

The paper provides the first non-linear numerical validation of the pendulum model's applicability to prominence oscillations considering realistic magnetic field reactions.

Findings

The pendulum model accurately describes LALOs even with weak magnetic fields.

Numerical simulations confirm the model's robustness against magnetic field reactions.

Implications for prominence seismology and magnetic field geometry inference.

Abstract

Large-amplitude longitudinal oscillations (LALOs) in prominences are spectacular manifestations of the solar activity. In such events nearby energetic disturbances induce periodic motions on filaments with displacements comparable to the size of the filaments themselves and with velocities larger than 20 km/s. The pendulum model, in which the gravity projected along a rigid magnetic field is the restoring force, was proposed to explain these events. However, it can be objected that in a realistic situation where the magnetic field reacts to the mass motion of the heavy prominence, the simplified pendulum model could be no longer valid. We have performed non-linear time-dependent numerical simulations of LALOs considering a dipped magnetic field line structure. In this work we demonstrate that for even relatively weak magnetic fields the pendulum model works very well. We therefore validate the pendulum model and show its robustness, with important implications for prominence seismology purposes. With this model it is possible to infer the geometry of the dipped field lines that support the prominence.