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Abstract Determining the relative contribution of solar flares versus coronal mass ejections in large solar energetic particle (SEP) events is a long-standing problem. Flare-accelerated particles may travel through complex magnetic fields in the eruption region and escape into interplanetary space, thereby contributing to large SEP events. The process by which flare accelerated particles are released into the heliosphere is poorly understood and yet is critical to advancing our understanding of SEPs. In this work, we address the release problem by solving the focused transport equation in the context of a 2.5D ARMS magnetohydrodynamic simulation of a breakout coronal mass ejection (CME)/flare event. We find that particles accelerated by flare reconnection can be released into interplanetary space through interchange reconnection between closed and open field lines. These particles can contribute directly to SEP events and may become an important seed population for further acceleration by CME-driven shocks. Additionally, we find that the energetic particle fluxes in the inner heliosphere remain elevated for an extended period, allowing them to contribute to SEP acceleration by subsequent CMEs. This study represents the first direct particle modeling of how flare-accelerated particles can contribute to major SEP events.
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Modeling the Energy Release in Solar Eruptive Events
Magnetic reconnection in a flare current sheet is widely believed to be the main energy release process powering solar flares and coronal mass ejections (CMEs). Modeling this process and determining the channels for the energy release, mass motions, and heating has long been a major goal in space science. We present results from a two-fluid magnetohydrodynamic simulation of an eruptive flare/CME using a newly developed version of the Space Weather Modeling Framework that incorporates two major advances in numerical capability. First, we use the STatistical InjecTion of Condensed Helicity formalism for the energy buildup, so that we start with a potential-field minimum-energy state and slowly form a sheared filament channel over a polarity inversion line as is observed on the Sun. Second, we use a new formulation of the plasma energetics that is explicitly energy conserving while calculating separate electron and ion temperatures and separate parallel and perpendicular pressures, as desired. For this first simulation with our new model, we opted for the nonadiabatic heating to go solely into the protons and for an isotropic pressure. We discuss the resulting energetics of the reconnection and, in particular, the plasma heating in the reconnecting current sheets, mass acceleration, and shock formation. We also discuss the implications of our results for flare/CME observations and for understanding solar eruptions in general.
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- Award ID(s):
- 2229337
- PAR ID:
- 10674889
- Publisher / Repository:
- IOP Publishers
- Date Published:
- Journal Name:
- The Astrophysical Journal
- Volume:
- 995
- Issue:
- 2
- ISSN:
- 0004-637X
- Page Range / eLocation ID:
- 221
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
-
Accepted Manuscript
- Journal Article:
- https://doi.org/10.3847/1538-4357/ae2479
