Detection of high frequency oscillations and damping from multi-slit spectroscopic observations of the corona

TL;DR

This study used high-cadence spectroscopic observations during a solar eclipse to detect high-frequency coronal oscillations and their damping, providing insights into coronal heating mechanisms.

Contribution

First detection of damping in high-frequency coronal oscillations using wavelet analysis during a solar eclipse observation.

Findings

Oscillations with periods of 6-25 seconds were observed.

Damping of oscillations with periods around 10 seconds was detected.

Results suggest MHD waves may significantly contribute to coronal heating.

Abstract

During the total solar eclipse of 11 July 2010, multi-slit spectroscopic observations of the solar corona were performed from Easter Island, Chile. To search for high-frequency waves, observations were taken at a high cadence in the green line at 5303 A due to [Fe xiv] and the red line at 6374 A due to [Fe x]. The data are analyzed to study the periodic variations in the intensity, Doppler velocity and line width using wavelet analysis. The data with high spectral and temporal resolution enabled us to study the rapid dynamical changes within coronal structures. We find that at certain locations each parameter shows significant oscillation with periods ranging from 6 - 25 s. For the first time, we could detect damping of high-frequency oscillations with periods of the order of 10 s. If the observed damped oscillations are due to magnetohydrodynamic (MHD) waves then they can contribute significantly in the heating of the corona. From a statistical study we try to characterize the nature of the observed oscillations while looking at the distribution of power in different line parameters.