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Highly Energetic Electrons Accelerated in Strong Solar Flares as a Preferred Driver of Sunquakes

Authors :
H. Wu
Y. Dai
M. D. Ding
Source :
The Astrophysical Journal Letters, Vol 943, Iss 1, p L6 (2023)
Publication Year :
2023
Publisher :
IOP Publishing, 2023.

Abstract

Sunquakes are enhanced seismic waves excited in some energetic solar flares. Up to now, their origin has still been controversial. In this Letter, we select and study 20 strong flares in Solar Cycle 24, whose impulse phase is fully captured by the Reuven Ramaty High Energy Solar Spectroscopic Imager. For 11 out of 12 sunquake-active flares in our sample, the hard X-ray emission shows a good temporal and spatial correlation with the white-light enhancement and the sunquake. Spectral analysis also reveals a harder photon spectrum that extends to several hundred keV, implying a considerable population of flare-accelerated nonthermal electrons at high energies. Quantitatively, the total energy of electrons above 300 keV in sunquake-active flares is systematically different from that in sunquake-quiet flares, while the difference is marginal for electrons above 50 keV. All these facts support highly energetic electrons as a preferred driver of the sunquakes. Such an electron-driven scenario can be reasonably accommodated in the framework of a recently proposed selection rule for sunquake generation. For the remaining one event, the sunquake epicenter is cospatial with a magnetic imprint, i.e., a permanent change of magnetic field on the photosphere. Quantitative calculation shows that the flare-induced downward Lorentz force can do enough work to power the sunquake, acting as a viable sunquake driver for this specific event.

Details

Language :
English
ISSN :
20418213 and 20418205
Volume :
943
Issue :
1
Database :
Directory of Open Access Journals
Journal :
The Astrophysical Journal Letters
Publication Type :
Academic Journal
Accession number :
edsdoj.43a8ce0525964fc1904fae65ea0f217a
Document Type :
article
Full Text :
https://doi.org/10.3847/2041-8213/acb0d1