Prominence-cavity regions observed using SWAP 174A filtergrams and simultaneous eclipse flash spectra

TL;DR

This study compares SWAP 174A images with eclipse flash spectra to analyze prominence-cavity regions, revealing plasma density depressions around prominences through combined imaging and spectral data.

Contribution

It provides a novel combined analysis of space-based EUV images and eclipse spectra to study prominence cavities and their plasma density characteristics.

Findings

Prominence cavities show plasma density depressions.

Intensity depressions observed in both eclipse and SWAP images.

Coronal plasma density variations are linked to prominence structures.

Abstract

Images from the SWAP (Proba 2 mission) taken at 174A in the Fe IX/X lines are compared to simultaneous slitless flash spectra taken during the last solar total eclipse of July, 11th 2010. Many faint low excitation emission lines together with the HeI and HeII Paschen Alpha chromospheric lines are recorded on eclipse spectra where regions of limb prominences are obtained with space-borne imagers. We consider a deep flash spectrum obtained by summing 80 individual spectra to show the intensity modulations of the continuum. Intensity depressions are observed around the prominences in both eclipse and SWAP images. The prominence cavities are interpreted as a relative depression of plasma density, produced inside the corona surrounding the prominences. Photometric measurements are shown at different scales and different, spectrally narrow, intervals for both the prominences and the coronal background.