On the Origin of Hard X-Ray Emissions from the Behind-the-limb Flare on 2014 September 1



: Wu Yihong, Rouillard Alexis P, Kouloumvakos Athanasios, Vainio Rami, Afanasiev Alexandr N, Plotnikov Illya, Murphy Ronald J, Mann Gottfried J, Warmuth Alexander

Publisher: IOP PUBLISHING LTD

: 2021

: Astrophysical Journal

: ASTROPHYSICAL JOURNAL

: ASTROPHYS J

: ARTN 163

: 909

: 2

: 16

: 0004-637X

DOI: https://doi.org/10.3847/1538-4357/abdc20

: https://research.utu.fi/converis/portal/detail/Publication/55574206


The origin of hard X-rays and gamma-rays emitted from the solar atmosphere during occulted solar flares is still debated. The hard X-ray emissions could come from flaring loop tops rising above the limb or coronal mass ejection shock waves, two by-products of energetic solar storms. For the shock scenario to work, accelerated particles must be released on magnetic field lines rooted on the visible disk and precipitate. We present a new Monte Carlo code that computes particle acceleration at shocks propagating along large coronal magnetic loops. A first implementation of the model is carried out for the 2014 September 1 event, and the modeled electron spectra are compared with those inferred from Fermi Gamma-ray Burst Monitor (GBM) measurements. When particle diffusion processes are invoked, our model can reproduce the hard electron spectra measured by GBM nearly 10 minutes after the estimated on-disk hard X-rays appear to have ceased from the flare site.

Last updated on 2024-26-11 at 15:30