@article{03eaf84a1ad24e25bee1a2b86be018d8,
title = "Applying the Weighted Horizontal Magnetic Gradient Method to a Simulated Flaring Active Region",
abstract = "Here, we test the weighted horizontal magnetic gradient (WGM) as a flare precursor, introduced by Kors{\'o}s et al., by applying it to a magnetohydrodynamic (MHD) simulation of solar-like flares. The preflare evolution of the WGM and the behavior of the distance parameter between the area-weighted barycenters of opposite-polarity sunspots at various heights is investigated in the simulated δ-type sunspot. Four flares emanated from this sunspot. We found the optimum heights above the photosphere where the flare precursors of the WGM method are identifiable prior to each flare. These optimum heights agree reasonably well with the heights of the occurrence of flares identified from the analysis of their thermal and ohmic heating signatures in the simulation. We also estimated the expected time of the flare onsets from the duration of the approaching-receding motion of the barycenters of opposite polarities before each single flare. The estimated onset time and the actual time of occurrence of each flare are in good agreement at the corresponding optimum heights. This numerical experiment further supports the use of flare precursors based on the WGM method.",
keywords = "Sun: evolution, Sun: flares, sunspots",
author = "Kors{\'o}s, {M. B.} and P. Chatterjee and R. Erd{\'e}lyi",
note = "Funding Information: We thank the anonymous referee for a very careful reading of our manuscript that has led to a marked improvement in the clarity of this paper. M.B.K. is grateful to the University of Sheffield and the Hungarian Academy of Sciences for the support received. M.B.K. also acknowledges the open research program of CAS Key Laboratory of Solar Activity, National Astronomical Observatories, No. KLSA201610. P.C. thanks the University of Sheffield for hospitality and support for a visit during which this work was initiated and the CAS PIFI project 2017VMC0002 and National Astronomical Observatories, Beijing, for support. The simulation was carried out on NASA{\textquoteright}s Pleiades supercomputer under GID s1061. P.C. also acknowledges computing time awarded on the PARAM Yuva-II supercomputer at C-DAC, India, under the grant name Hydromagnetic-Turbulence-PR. We have used the 3D visualization software Paraview for volume rendering and field line plotting. R.E. is grateful to the Science and Technology Facilities Council (STFC; grant Nos. ST/ L006316/1 and ST/M000826/1) UK and the Royal Society for their support. The authors also express their gratitude to Christopher J. Nelson and Michael S. Ruderman (both at University of Sheffield, UK) for a number of useful discussions and improving the manuscript. Funding Information: M.B.K. also acknowledges the open research program of CAS Key Laboratory of Solar Activity, National Astronomical Observatories, No. KLSA201610. P.C. thanks the University of Sheffield for hospitality and support for a visit during which this work was initiated and the CAS PIFI project 2017VMC0002 and National Astronomical Observatories, Beijing, for support. Publisher Copyright: {\textcopyright} 2018. The American Astronomical Society. All rights reserved. Copyright: Copyright 2018 Elsevier B.V., All rights reserved.",
year = "2018",
month = apr,
day = "20",
doi = "10.3847/1538-4357/aab891",
language = "English",
volume = "857",
journal = "Astrophysical Journal",
issn = "0004-637X",
publisher = "IOP Publishing",
number = "2",
}