[P-EM14] Frontiers in solar physics

[PEM14-P10] Investigating differences of magnetic fields in Solar active regions that produce eruptive and confined flares

*Ichiro Goto¹, Kanya Kusano¹, KD Leka^1,2 (1.Institute for Space-Earth Environmental Research Higashiyama Campus, Nagoya University, 2.NorthWest Research Associates)

Keywords:The sun, flares, CMEs

Solar flares and coronal mass ejections (CMEs) are massive eruptions in the solar corona. They may affect geospace and impact social infrastructures. However, the relationship between flares and CMEs is not clearly understood yet. Sometimes CMEs occur with solar flares but the relationship is not 1:1. The impacts from flares and CMEs are different, so, it is important to investigate what properties in the source region (active region) of these events determines whether an eruptive flare (flare with CME) or a confined flare (only a flare) will be produced. Recently, Liu et al. (2022) analyzed the properties of the force-free “twist” parameter α for multiple active regions, and showed that the α averaged over flaring regions evolves differently between the regions producing eruptive flares and producing confined flares: in the former, it decreases before the flare onset and increases immediately after the flare but in the latter the average α did not significantly change before and after the flare. However, the cause of this difference is not yet understood. The objective of this study is to investigate the reason for the different behavior, for an eventual goal of predicting CMEs. To this end, we propose a hypothesis that the distribution of high α concentrates near the polarity inversion line (PIL) before the onset of eruptive flare due to this end, we propose a hypothesis that the distribution of high α concentrates near the polarity inversion line (PIL) before the onset of eruptive flare because the strong magnetic twist near the PIL is suggested to be related to the onset of flares (Kusano et al. 2020).To verify this hypothesis, we analyze spatiotemporal structure of several parameters related to the non-potential magnetic fields (α, shear angle, non-potential field intensity, etc.) by calculating their moments near the flare-associated PILs and evaluating their relationship to eruptivity.