Interaction of solar jets with filaments: Triggering of large-amplitude filament oscillations

TL;DR

This study provides observational evidence that solar jets can trigger large-amplitude filament oscillations, supporting recent numerical models and enhancing understanding of filament dynamics and magnetic field interactions.

Contribution

The paper presents two case studies demonstrating that solar jets can initiate filament oscillations, aligning with recent 2.5D MHD numerical simulations and clarifying the role of magnetic reconnection.

Findings

Filament oscillations have periods of 70-80 minutes.

Jets are associated with weak flares and no EUV waves.

Minimum magnetic field strength in filaments is around 30 Gauss.

Abstract

Large-amplitude oscillations (LAOs) are often detected in filaments. Using multiwavelength observations, their origin can be traced back to the interaction with eruptions and jets. We present two different case studies as observational evidence in support of 2.5D MHD numerical experiments that show that the LAOs in the filament channels can be initiated by solar jets. In the two studied events, we can identify a quadrupolar configuration with an X-point at the top of the parasitic region suggestive of a classical null-point. A reconnection flow emanates from this structure leading to a jet that propagates along the filament channel. In both cases we can identify the quiescent and eruptive phases of the jet. The triggered LAOs have periods of around 70-80 minutes and are damped after a few oscillations. The minimum magnetic field intensity inferred with seismology for the filament turns out to be around 30 Gauss. We conclude that the two case studies are consistent with the recent numerical model of Luna and Moreno-Insertis (2021), in which the LAOs are initiated by jets. The relationship between the onset of the jet and filament oscillations is straight-forward for the first case and less for the second case. In the second event, although there is some evidence, we cannot rule out other possibilities such as activity unrelated to the null-point or changes in the magnetic structure of the filament. Both jets are associated with very weak flares which did not launch any EUV wave. Therefore the role of EUV waves for triggering the filament oscillations can be eliminated for these two case.