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arXiv · 2101.05401

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

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

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Yihong Wu, Alexis P. Rouillard, Athanasios Kouloumvakos, Rami Vainio, Alexandr N. Afanasiev, Illya Plotnikov, Ronald J. Murphy, Gottfried J. Mann, Alexander Warmuth. 2021-01-14. On the origin of hard X-ray emissions from the behind-the-limb flare on 2014 September 1. https://doi.org/10.3847/1538-4357%2Fabdc20

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