On the origin of hard X-ray emissions from the behind-the-limb flare on 2014 September 1

Abstract

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 Ejections (CME) 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 ten minutes after the estimated on-disk hard X-rays appear to have ceased from the flare site.

arXiv comment24 pages, 14 figures, Accepted for publication in The Astrophysical Journal

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Cited by in corpus (2)

• The coupling of an EUV coronal wave and ion acceleration in a Fermi-LAT behind-the-limb solar flare
• Evidence for flare-accelerated particles in large scale loops in the behind-the-limb gamma-ray solar flare of September 29, 2022