Coronal loop physical parameters from the analysis of multiple observed transverse oscillations

TL;DR

This study uses Bayesian hierarchical seismology to analyze transverse oscillations in solar coronal loops, inferring key physical parameters like Alfven travel times and density contrast with high confidence.

Contribution

It introduces a global Bayesian analysis method for coronal loop parameters based on multiple observed oscillations, improving parameter inference accuracy.

Findings

Alfven travel times are between 100 and 540 seconds with 95% probability.

Density contrast between loop interior and surroundings is between 2.3 and 6.9 with 95% probability.

The method provides global distributions that can inform individual loop analyses.

Abstract

The analysis of quickly damped transverse oscillations of solar coronal loops using magneto-hydrodynamic seismology allow us to infer physical parameters that are difficult to measure otherwise. Under the assumption that such damped oscillations are due to the resonant conversion of global modes into Alfven oscillations of the tube surface, we carry out a global seismological analysis of a large set of coronal loops. A Bayesian hierarchical method is used to obtain distributions for coronal loop physical parameters by means of a global analysis of a large number of observations. The resulting distributions summarise global information and constitute data-favoured information that can be used for the inversion of individual events. The results strongly suggest that internal Alfven travel times along the loop are larger than 100 s and smaller than 540 s with 95% probability. Likewise, the density contrast between the loop interior and the surrounding is larger than 2.3 and below 6.9 with 95% probability.