skip to main content

Title: Global numerical modeling of energetic proton acceleration in a coronal mass ejection traveling through the solar corona

The acceleration of protons and electrons to high (sometimes GeV/nucleon) energies by solar phenomena is a key component of space weather. These solar energetic particle (SEP) events can damage spacecraft and communications, as well as present radiation hazards to humans. In-depth particle acceleration simulations have been performed for idealized magnetic fields for diffusive acceleration and particle propagation, and at the same time the quality of MHD simulations of coronal mass ejections (CMEs) has improved significantly. However, to date these two pieces of the same puzzle have remained largely decoupled. Such structures may contain not just a shock but also sizable sheath and pileup compression regions behind it, and may vary considerably with longitude and latitude based on the underlying coronal conditions. In this work, we have coupled results from a detailed global three-dimensional MHD time-dependent CME simulation to a global proton acceleration and transport model, in order to study time-dependent effects of SEP acceleration between 1.8 and 8 solar radii in the 2005 May 13 CME. We find that the source population is accelerated to at least 100 MeV, with distributions enhanced up to six orders of magnitude. Acceleration efficiency varies strongly along field lines probing different regions of themore » dynamically evolving CME, whose dynamics is influenced by the large-scale coronal magnetic field structure. We observe strong acceleration in sheath regions immediately behind the shock.« less
Authors:
;  [1] ;  [2] ;  [3] ;  [4] ;  [5] ;  [6]
  1. Department of Astronomy, Boston University, Boston, MA 02215 (United States)
  2. NASA/Goddard Space Flight Center, Greenbelt, MD 20771 (United States)
  3. Institute for the Study of Earth, Oceans, and Space, University of New Hampshire, Durham, NH 03824-3525 (United States)
  4. Department of Space Science, Southwest Research Institute, San Antonio, TX (United States)
  5. Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States)
  6. Center for Space Environment Modeling, University of Michigan, Ann Arbor, MI 48109-2143 (United States)
Publication Date:
OSTI Identifier:
22342007
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 778; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ACCELERATION; COMPRESSION; DISTRIBUTION; EFFICIENCY; ELECTRONS; EMISSION; GEV RANGE; HELIOSPHERE; MAGNETIC FIELDS; MAGNETOHYDRODYNAMICS; MASS; MEV RANGE; PROTONS; SHOCK WAVES; SIMULATION; SOLAR CORONA; SUN; TIME DEPENDENCE; TRANSPORT THEORY