MHD Seismology of a loop-like filament tube by observed kink waves

TL;DR

This paper presents observational evidence of global kink oscillations in a solar filament triggered by a flare, and uses seismology to estimate the filament's inhomogeneity scale based on damping analysis.

Contribution

It provides the first detailed seismological analysis of a filament kink wave using observed damping times and periods, applying resonant absorption theory.

Findings

Detected kink oscillations with periods of 61-67 minutes.

Measured damping times of 92-117 minutes.

Estimated inhomogeneity length-scale as 0.34-0.44 times the filament radius.

Abstract

We report and analyze the observational evidence of global kink oscillations in a solar filament as observed in H alpha by National Solar Observatory (NSO)/Global Oscillation Network Group (GONG) instrument. An M1.1-class flare in active region 11692 on 2013 March 15 induced a global kink mode in the filament lying in the south-west of AR11692.We find periods of about 61 - 67 minutes and damping times of 92 - 117 minutes at three vertical slice positions chosen in and around the filament apex. We find that the waves are damped. From the observed global kink mode period and damping time scale using the theory of resonant absorption we perform prominence seismology. We estimate a lower cut-off value for the inhomogeneity length-scale to be around 0.34 - 0.44 times the radius of the filament cross-section.