Thermal instability in the impulsive phase of solar flares with sub-THz component

Coronal rain is formed in the post-impulsive phase of solar flares due to the thermal instability of coronal plasma in EUV loops. As a result, the sub-terahertz (sub-THz) emission flux in the post-impulsive phase of solar flares can be increased due to the increasing of the optical thickness of the...

Full description

Saved in:
Bibliographic Details
Published in:Proceedings of the International Astronomical Union 2023-12, Vol.19 (S365), p.414-419
Main Authors: Smirnova, V. V., Tsap, Yu. T., Motorina, G. G., Morgachev, A. S., Bárta, M.
Format: Article
Language:English
Subjects:
Coronal loops
Emission analysis
Optical thickness
Poster Paper
Radiation
Rain
Solar corona
Solar flares
Thermal instability
Two dimensional analysis
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Coronal rain is formed in the post-impulsive phase of solar flares due to the thermal instability of coronal plasma in EUV loops. As a result, the sub-terahertz (sub-THz) emission flux in the post-impulsive phase of solar flares can be increased due to the increasing of the optical thickness of the thermal source. This suggests that sub-THz observations can be used as a diagnostic tool for coronal rain. This work is aimed to analyse the relationship between the sub-THz radiation and variations of the temperature and the emission measure of the EUV coronal plasma during the post-impulsive phase of the SOL2022-05-04T08:45 solar flare. Based on the two-dimensional temperature and emission measure distributions obtained from the AIA/SDO EUV intensity data, it was found that the temperature decreases whereas the emission measure reaches the maximum near the sub-THz flare peak. This circumstance and peculiarities of the radiation time profiles in different wave ranges show evidence in favor of the significant contribution of the thermal coronal loop plasma to the flare sub-THz radiation at least for some flare events. The sub-THz emission may be associated with a coronal condensation, accompanied by the formation of coronal rain.
ISSN:1743-9213
1743-9221
DOI:10.1017/S1743921323005185