Acceleration of solar-energetic particles by shocks

Joe Giacalone, József Kóta

Research output: Contribution to journalArticlepeer-review

23 Scopus citations


Our current understanding of the acceleration of solar-energetic particles is reviewed. The emphasis in this paper is on analytic theory and numerical modeling of the physics of diffusive shock acceleration. This mechanism naturally produces an energy spectrum that is a power law over a given energy interval that is below a characteristic energy where the spectrum has a break, or a rollover. This power law is a common feature in the observations of all types of solar-energetic particles, and not necessarily just those associated with shock waves (e.g. events associated with impulsive solar flares which are often described in terms of resonant stochastic acceleration). Moreover, the spectral index is observed to have remarkably little variability from one event to the next (about 50%). Any successful acceleration mechanism must be able to produce this feature naturally and have a resulting power-law index that does not depend on physical parameters that are expected to vary considerably. Currently, only diffusive shock acceleration does this.

Original languageEnglish (US)
Pages (from-to)277-288
Number of pages12
JournalSpace Science Reviews
Issue number1-4
StatePublished - Jun 2006


  • Coronal mass ejections
  • Particle acceleration
  • Solar energetic particles
  • Solar magnetic fields

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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