Survey of Magnetic Field Parameters Associated With Large Solar Flares

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Hauptverfasser: Li, Ting, Zheng, Yanfang, Li, Xuefeng, Hou, Yijun, Li, Xuebao, Zhang, Yining, Chen, Anqin
Format: Preprint
Veröffentlicht: 2024
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author Li, Ting
Zheng, Yanfang
Li, Xuefeng
Hou, Yijun
Li, Xuebao
Zhang, Yining
Chen, Anqin
author_facet Li, Ting
Zheng, Yanfang
Li, Xuefeng
Hou, Yijun
Li, Xuebao
Zhang, Yining
Chen, Anqin
contents Until now, how the magnetic fields in M/X-class flaring active regions (ARs) differ from C-class flaring ARs remains unclear. Here, we calculate the key magnetic field parameters within the area of high photospheric free energy density (HED region) for 323 ARs (217 C- and 106 M$/$X-flaring ARs), including total photospheric free magnetic energy density E$_{free}$, total unsigned magnetic flux $Φ$$_{HED}$, mean unsigned current helicity h$_{c}$, length of the polarity inversion lines $L$$_{PIL}$ with a steep horizontal magnetic gradient, etc., and compare these with flare/coronal mass ejection (CME) properties. We first show the quantitative relations among the flare intensity, the eruptive character and $Φ$$_{HED}$. We reveal that $Φ$$_{HED}$ is a measure for the GOES flux upper limit of the flares in a given region. For a given $Φ$$_{HED}$, there exists the lower limit of F$_\mathrm{SXR}$ for eruptive flares. This means that only the relatively strong flares with the large fraction of energy release compared to the total free energy are likely to generate a CME. We also find that the combinations of E$_{free}$-$L$$_{PIL}$ and E$_{free}$-h$_{c}$ present a good ability to distinguish between C-class and M$/$X-class flaring ARs. Using determined critical values of E$_{free}$ and $L$$_{PIL}$, one predicts correctly 93 out of 106 M/X-class flaring ARs and 159/217 C-class flaring ARs. The large $L$$_{PIL}$ or h$_{c}$ for M$/$X-class flaring ARs probably implies the presence of a compact current with twisted magnetic fields winding about it.
format Preprint
id arxiv_https___arxiv_org_abs_2402_18890
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Survey of Magnetic Field Parameters Associated With Large Solar Flares
Li, Ting
Zheng, Yanfang
Li, Xuefeng
Hou, Yijun
Li, Xuebao
Zhang, Yining
Chen, Anqin
Solar and Stellar Astrophysics
Until now, how the magnetic fields in M/X-class flaring active regions (ARs) differ from C-class flaring ARs remains unclear. Here, we calculate the key magnetic field parameters within the area of high photospheric free energy density (HED region) for 323 ARs (217 C- and 106 M$/$X-flaring ARs), including total photospheric free magnetic energy density E$_{free}$, total unsigned magnetic flux $Φ$$_{HED}$, mean unsigned current helicity h$_{c}$, length of the polarity inversion lines $L$$_{PIL}$ with a steep horizontal magnetic gradient, etc., and compare these with flare/coronal mass ejection (CME) properties. We first show the quantitative relations among the flare intensity, the eruptive character and $Φ$$_{HED}$. We reveal that $Φ$$_{HED}$ is a measure for the GOES flux upper limit of the flares in a given region. For a given $Φ$$_{HED}$, there exists the lower limit of F$_\mathrm{SXR}$ for eruptive flares. This means that only the relatively strong flares with the large fraction of energy release compared to the total free energy are likely to generate a CME. We also find that the combinations of E$_{free}$-$L$$_{PIL}$ and E$_{free}$-h$_{c}$ present a good ability to distinguish between C-class and M$/$X-class flaring ARs. Using determined critical values of E$_{free}$ and $L$$_{PIL}$, one predicts correctly 93 out of 106 M/X-class flaring ARs and 159/217 C-class flaring ARs. The large $L$$_{PIL}$ or h$_{c}$ for M$/$X-class flaring ARs probably implies the presence of a compact current with twisted magnetic fields winding about it.
title Survey of Magnetic Field Parameters Associated With Large Solar Flares
topic Solar and Stellar Astrophysics
url https://arxiv.org/abs/2402.18890