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Assessing the reliability of magnetic helicity as indicator for solar eruptivity

Julia K. Thalmann - University of Graz, Institute of Physics/IGAMLuis Linan - LESIA, Observatoire de Paris, Universite PSLFranceKostas Moraitis - LESIA, Observatoire de Paris, Universite PSLFranceXudong Sun - Institute for Astronomy, University of HawaiiUnited StatesEtienne Pariat - LESIA, Observatoire de Paris, Universite PSLFranceGherardo Valori - MSSL, University College LondonUnited KingdomManu Gupta - University of Graz, Institute of Physics/IGAMAustriaKevin Dalmasse - IRAP, Universite de ToulouseFrance

Session: The Solar Sources of Space Weather


To this date, we still lack a full understanding of the physics behind explosive solar phenomena. Thus, related research still struggles to find reliable indicators for upcoming flare activity and also for the according potential to evolve into a coronal mass ejection. The latter, however, is essential for any attempt to predict the induced Space Weather on Earth. Until present, no single observation- or model-based parameter has been singled out as a promising candidate to unambiguously characterize the flaring potential of active regions, yet a helicity-based parameter attracted recent attention. The so-called helicity ratio quantifies the fraction of non-potential magnetic helicity in the active-region corona, associated to present intense electric currents. Based on a limited sample of solar active regions, we find indications that the helicity ratio indeed marks the eruptive potential of solar active regions. Equally important, we demonstrate the high sensitivity of magnetic helicity estimates on the quality of underlying 3D nonlinear force-free coronal magnetic field model, in particular its level of solenoidality, and subsequently provide recipes in order to deduce corresponding highly reliable estimates.

Approaching deadlines:

Registration opens:

16 July 2020

Abstract submission opens:

16 July 2020

European Space Weather Medals:

6 September 2020

Registration deadline:

25 September 2020

Registration deadline: [extended]

10 October 2020

Abstract submission deadline:

4 September 2020