Shock-Drift Acceleration and Diffusive Shock Acceleration at CME-Driven Shocks
Abstract
The origin of hard X-ray and gamma-ray emissions from the solar atmosphere during solar flares is still highly debated. A possible explanation is that particles accelerated by shock waves ahead of expanding Coronal Mass Ejection (CME) propagate from the shock to the visible solar disk. Past studies have shown that during flare-occulted events the onset of the particle events occur when the shock connects magnetically to the visible disk. This connection is pre-dominantly via magnetic loops near onset. Using recent imaging of the NASA STEREO, SoHO and SDO spacecrafts, we determine the time-dependent 3-dimensional distribution of the expansion speed, Mach number and other properties of the coronal shock. We combine our advanced coronal shock models with our newly developed Shock-Drift Acceleration (SDA) and Diffusive Shock Acceleration (DSA) models to simulate particle production and transport from the shock to the chromosphere. We quantify for the first time the contribution of mirroring to both the acceleration process and transport of particles. The results of these simulations for a specific event (1 September 2014) show that electrons and protons can be accelerated to MeV and GeV respectively, and impact the solar surface producing hard X rays and gamma rays. Finally, we compare the numbers of energetic electrons and protons hitting the solar surface in our calculations with those inferred from Fermi GBM and LAT spectra with very promising results.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFMSH23B3402W
- Keywords:
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- 7829 Kinetic waves and instabilities;
- SPACE PLASMA PHYSICS;
- 7845 Particle acceleration;
- SPACE PLASMA PHYSICS;
- 7846 Plasma energization;
- SPACE PLASMA PHYSICS;
- 7851 Shock waves;
- SPACE PLASMA PHYSICS