A Data-Driven Analytic Model for Proton Acceleration by Large-Scale Solar Coronal Shocks

Abstract

We have recently studied the development of an eruptive filament-driven, large-scale off-limb coronal bright front (OCBF) in the low solar corona (Kozarev et al. 2015), using remote observations from Solar Dynamics Observatory's Advanced Imaging Assembly EUV telescopes. In that study, we obtained high-temporal resolution estimates of the OCBF parameters regulating the efficiency of charged particle acceleration within the theoretical framework of diffusive shock acceleration (DSA). These parameters include the time-dependent front size, speed, and strength, as well as the upstream coronal magnetic field orientations with respect to the front's surface normal direction. Here we present an analytical particle acceleration model, specifically developed to incorporate the coronal shock/compressive front properties described above, derived from remote observations. We verify the model's performance through a grid of idealized case runs using input parameters typical for large-scale coronal shocks, and demonstrate that the results approach the expected DSA steady-state behavior. We then apply the model to the event of May 11, 2011 using the OCBF time-dependent parameters derived in Kozarev et al. (2015). We find that the compressive front likely produced energetic particles as low as 1.3 solar radii in the corona. Comparing the modeled and observed fluences near Earth, we also find that the bulk of the acceleration during this event must have occurred above 1.5 solar radii. With this study we have taken a first step in using direct observations of shocks and compressions in the innermost corona to predict the onsets and intensities of SEP events.

Submitted to The Astrophysical Journal on 11 June, 2016; Accepted for publication on August 22, 2016

References in corpus (5)

• The formation heights of coronal shocks from 2D density and Alfvén speed maps
• Off-limb Solar Coronal Wavefronts From SDO/AIA EUV Observations - Implications For Particle Production
• Quasiperiodic acceleration of electrons by a plasmoid-driven shock in the solar atmosphere
• Global Numerical Modeling of Energetic Proton Acceleration in a Coronal Mass Ejection Traveling through the Solar Corona
• Properties of a Coronal Shock Wave as A Driver of Early SEP Acceleration

Cited by in corpus (1)

• On the expected $\gamma$-ray emission from nearby flaring stars