Thumbnail
Access Restriction
Open

Author Kocharov, L. ♦ Laitinen, T. ♦ Vainio, R. ♦ Afanasiev, A. ♦ Mursula, K. ♦ Ryan, J. M.
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword ASTROPHYSICS, COSMOLOGY AND ASTRONOMY ♦ ACCELERATION ♦ COMPARATIVE EVALUATIONS ♦ INTERPLANETARY SPACE ♦ MAGNETIC FIELDS ♦ MASS ♦ PIONS ♦ PLASMA ♦ SHOCK WAVES ♦ SOLAR PROTONS ♦ SPHERICAL CONFIGURATION ♦ STOCHASTIC PROCESSES ♦ SUN ♦ SURFACES ♦ TURBULENCE ♦ WAVE PROPAGATION
Abstract With the first observations of solar γ-rays from the decay of pions, the relationship of protons producing ground level enhancements (GLEs) on the Earth to those of similar energies producing the γ-rays on the Sun has been debated. These two populations may be either independent and simply coincident in large flares, or they may be, in fact, the same population stemming from a single accelerating agent and jointly distributed at the Sun and also in space. Assuming the latter, we model a scenario in which particles are accelerated near the Sun in a shock wave with a fraction transported back to the solar surface to radiate, while the remainder is detected at Earth in the form of a GLE. Interplanetary ions versus ions interacting at the Sun are studied for a spherical shock wave propagating in a radial magnetic field through a highly turbulent radial ray (the acceleration core) and surrounding weakly turbulent sector in which the accelerated particles can propagate toward or away from the Sun. The model presented here accounts for both the first-order Fermi acceleration at the shock front and the second-order, stochastic re-acceleration by the turbulence enhanced behind the shock. We find that the re-acceleration is important in generating the γ-radiation and we also find that up to 10% of the particle population can find its way to the Sun as compared to particles escaping to the interplanetary space.
ISSN 0004637X
Educational Use Research
Learning Resource Type Article
Publisher Date 2015-06-10
Publisher Place United States
Journal Astrophysical Journal
Volume Number 806
Issue Number 1


Open content in new tab

   Open content in new tab