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Coronal shock acceleration under scatter-free upstream conditions

  • Authors: Vainio, R.; Laitinen, T.
  • Publication: 35th COSPAR Scientific Assembly. Held 18 - 25 July 2004, in Paris, France., p.1817, 2004
  • Theoretical study
  • ADS link
  • Abstract: Particle acceleration by coronal shock waves is studied. Efficient acceleration requires particles to interact with the shock many times before substantial energy gains can be expected. In diffusive shock acceleration models, particles scatter off low-frequency plasma waves or turbulence around the shock, which results in particle trajectories crossing the shock front many times. We study an alternative to the standard diffusive shock acceleration model: an oblique coronal shock wave propagating toward the solar surface on open field lines without upstream turbulence but with a large magnetic mirror ratio between the footpoint and the shock location. Such shocks can be either freely propagating or driven shock waves, and they would be related to the initial phases of particle events, when the erupting plasma has scales of the order of a solar radius. Our simulations reveal that the modeled shocks are able to efficiently accelerate ions up to energies from a few to a few tens of MeVs per nucleon, depending on the parameters of the shock wave and of the underlying magnetic field. These energies can be further increased by allowing particle scattering off upstream turbulence.

Created by mevali. Last Modification: Wednesday 23 of May, 2007 08:25:37 UTC by mevali.