SMuK 2021 – scientific programme

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EP: Fachverband Extraterrestrische Physik

EP 1: Sun and Heliosphere I

EP 1.1: Invited Talk

Monday, August 30, 2021, 11:00–11:30, H7

The onset mechanism and a physics-based prediction of large solar flares — •Kanya Kusano — Institute for Space-Earth Environmental Research, Nagoya University, Nagoya, Japan

What determines the onset of large solar flares is not yet well understood, although various models have been proposed. Therefore, their prediction mostly relies on empirical methods, and the accurate prediction of large flares is still difficult. Here, we report a new physics-based method, κ-scheme, that can predict imminent large solar flares (Kusano et al. 2020, Science). The κ-scheme is based on the theoretical model that a small magnetic reconnection between two sheared magnetic loops triggers the new ideal MHD instability, named the double-arc instability (Ishiguro & Kusano 2017, ApJ), driving a solar flare. We applied the κ-scheme to 198 active regions (ARs) with the largest sunspots recorded from 2010 to 2017 using the SDO SHARP dataset. While only 7 ARs in them produced solar flares larger than class X2, we demonstrated that the κ-scheme could clearly discriminate the 6 ARs in them out of the ARs not producing the large flare. It is also shown that the κ-scheme can predict even the precise position where a large flare begins. Based on the results, we conclude that magnetic twist flux density close to a magnetic polarity inversion line determines when and where solar flares may occur and how large they can be. Finally, we also discuss an attempt to extend the κ-scheme to predict eruptive flares and coronal mass ejections (Lin et al. 2020 & 2021, ApJ).