Particle acceleration in the sun and heliosphere

Research output: Contribution to journalConference articlepeer-review


Our current understanding of the acceleration of energetic charged particles of heliospheric origin is reviewed. This paper outlines the key points, topics, and open issues that were discussed in the tutorial talk on energetic particles in the Sun and heliosphere. Because of the broad scope of this topic, much of the review focused on solar energetic particles. Moreover, while a few acceleration mechanisms were discussed, much of the emphasis was placed on the physics of diffusive shock acceleration. This mechanism naturally leads to power-law energy spectra which are commonly observed in the distributions of energetic particles in space plasmas. The theme of the tutorial was that the energy spectrum of most solar-energetic particle events, as well as other energetic nuclei of heliospheric origin, and galactic cosmic rays, share one common characteristic: they are all power laws below a characteristic energy. Moreover, the spectral index does not vary much from one event to the next. Any successful acceleration mechanism must be able to produce this feature naturally. Currently, only diffusive shock acceleration does this.

Original languageEnglish (US)
Pages (from-to)55-60
Number of pages6
JournalEuropean Space Agency, (Special Publication) ESA SP
Issue number592
StatePublished - 2005
EventSolar Wind 11/SOHO 16 - Connecting Sun and Heliosphere - Whistler, Canada
Duration: Jun 12 2005Jun 17 2005

ASJC Scopus subject areas

  • Aerospace Engineering
  • Space and Planetary Science


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