Issue |
A&A
Volume 689, September 2024
|
|
---|---|---|
Article Number | L11 | |
Number of page(s) | 6 | |
Section | Letters to the Editor | |
DOI | https://doi.org/10.1051/0004-6361/202451441 | |
Published online | 18 September 2024 |
Letter to the Editor
Magnetic helicity and energy budgets of jet events from an emerging solar active region
1
Section of Astrogeophysics, Department of Physics, University of Ioannina, Ioannina 45110, Greece
2
The Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723, USA
3
Research Center for Astronomy and Applied Mathematics, Academy of Athens, Athens 11527, Greece
4
HEPL Solar Physics, Stanford University, 94305-4085 Stanford, CA, USA
Received:
9
July
2024
Accepted:
26
August
2024
Using photospheric vector magnetograms obtained by the Helioseismic and Magnetic Imager onboard the Solar Dynamics Observatory and a magnetic connectivity-based method, we computed the magnetic helicity and free magnetic energy budgets of a simple bipolar solar active region (AR) during its magnetic flux-emergence phase, which lasted ∼47 h. The AR did not produce any coronal mass ejections (CMEs) or flares with an X-ray class above C1.0, but it was the site of 60 jet events during its flux-emergence phase. The helicity and free energy budgets of the AR were below established eruption-related thresholds throughout the interval we studied. However, in addition to their slowly varying evolution, each of the time profiles of the helicity and free energy budgets showed discrete localized peaks, with eight pairs of them occurring at times of jets emanating from the AR. These jets featured larger base areas and longer durations than the other jets of the AR. We estimated, for the first time, the helicity and free magnetic energy changes associated with these eight jets, which were in the ranges of 0.5 − 7.1 × 1040 Mx2 and 1.1 − 6.9 × 1029 erg, respectively. Although these values are one to two orders of magnitude smaller than those usually associated with CMEs, the relevant percentage changes were significant and ranged from 13% to 76% for the normalized helicity and from 9% to 57% for the normalized free magnetic energy. Our study indicates that jets may occasionally have a significant imprint in the evolution of helicity and free magnetic energy budgets of emerging ARs.
Key words: Sun: corona / Sun: flares / Sun: magnetic fields / Sun: photosphere
© The Authors 2024
Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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