skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Precipitation and Release of Solar Energetic Particles from the Solar Coronal Magnetic Field

Abstract

Most solar energetic particles (SEPs) are produced in the corona. They propagate through complex coronal magnetic fields subject to scattering and diffusion across the averaged field lines by turbulence. We examine the behaviors of particle transport using a stochastic 3D focused transport simulation in a potential field source surface model of coronal magnetic field. The model is applied to an SEP event on 2010 February 7. We study three scenarios of particle injection at (i) the compact solar flare site, (ii) the coronal mass ejection (CME) shock, and (iii) the EUV wave near the surface. The majority of particles injected on open field lines are able to escape the corona. We found that none of our models can explain the observations of wide longitudinal SEP spread without perpendicular diffusion. If the perpendicular diffusion is about 10% of what is derived from the random walk of field lines at the rate of supergranular diffusion, particles injected at the compact solar flare site can spread to a wide range of longitude and latitude, very similar to the behavior of particles injected at a large CME shock. Stronger pitch-angle scattering results in a little more lateral spread by holding the particles in themore » corona for longer periods of time. Some injected particles eventually end up precipitating onto the solar surface. Even with a very small perpendicular diffusion, the pattern of the particle precipitation can be quite complicated depending on the detailed small-scale coronal magnetic field structures, which could be seen with future sensitive gamma-ray telescopes.« less

Authors:
;  [1]
  1. Department of Physics and Space Sciences, Florida Institute of Technology, 150 W. University Blvd., Melbourne, FL 32901 (United States)
Publication Date:
OSTI Identifier:
22679874
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 846; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; DIFFUSION; EMISSION; EXTREME ULTRAVIOLET RADIATION; GAMMA RADIATION; INCLINATION; MAGNETIC FIELDS; MASS; PRECIPITATION; RANDOMNESS; SCATTERING; SIMULATION; SOLAR FLARES; SOLAR PARTICLES; STOCHASTIC PROCESSES; SUN; TELESCOPES; TURBULENCE

Citation Formats

Zhang, Ming, and Zhao, Lulu, E-mail: mzhang@fit.edu. Precipitation and Release of Solar Energetic Particles from the Solar Coronal Magnetic Field. United States: N. p., 2017. Web. doi:10.3847/1538-4357/AA86A8.
Zhang, Ming, & Zhao, Lulu, E-mail: mzhang@fit.edu. Precipitation and Release of Solar Energetic Particles from the Solar Coronal Magnetic Field. United States. doi:10.3847/1538-4357/AA86A8.
Zhang, Ming, and Zhao, Lulu, E-mail: mzhang@fit.edu. Sun . "Precipitation and Release of Solar Energetic Particles from the Solar Coronal Magnetic Field". United States. doi:10.3847/1538-4357/AA86A8.
@article{osti_22679874,
title = {Precipitation and Release of Solar Energetic Particles from the Solar Coronal Magnetic Field},
author = {Zhang, Ming and Zhao, Lulu, E-mail: mzhang@fit.edu},
abstractNote = {Most solar energetic particles (SEPs) are produced in the corona. They propagate through complex coronal magnetic fields subject to scattering and diffusion across the averaged field lines by turbulence. We examine the behaviors of particle transport using a stochastic 3D focused transport simulation in a potential field source surface model of coronal magnetic field. The model is applied to an SEP event on 2010 February 7. We study three scenarios of particle injection at (i) the compact solar flare site, (ii) the coronal mass ejection (CME) shock, and (iii) the EUV wave near the surface. The majority of particles injected on open field lines are able to escape the corona. We found that none of our models can explain the observations of wide longitudinal SEP spread without perpendicular diffusion. If the perpendicular diffusion is about 10% of what is derived from the random walk of field lines at the rate of supergranular diffusion, particles injected at the compact solar flare site can spread to a wide range of longitude and latitude, very similar to the behavior of particles injected at a large CME shock. Stronger pitch-angle scattering results in a little more lateral spread by holding the particles in the corona for longer periods of time. Some injected particles eventually end up precipitating onto the solar surface. Even with a very small perpendicular diffusion, the pattern of the particle precipitation can be quite complicated depending on the detailed small-scale coronal magnetic field structures, which could be seen with future sensitive gamma-ray telescopes.},
doi = {10.3847/1538-4357/AA86A8},
journal = {Astrophysical Journal},
number = 2,
volume = 846,
place = {United States},
year = {Sun Sep 10 00:00:00 EDT 2017},
month = {Sun Sep 10 00:00:00 EDT 2017}
}