Constraints on the acceleration of anomalous cosmic rays

J. R. Jokipii

Research output: Contribution to journalArticlepeer-review

52 Scopus citations


The recent determination of an upper limit of 0.2 pc on the distance to the source of the anomalous cosmic rays, and the implied upper limit on their age imposes a significant observational constraint on possible acceleration mechanisms. Adiabatic cooling in the expanding wind makes the constraints significantly more stringent. In the light of these constraints, the rate of second-order Fermi acceleration is much too low to play a significant role. Diffusive shock acceleration, even at the strong termination shock of the solar wind, is sufficient only if one discards the standard expression for the maximum acceleration rate based on the Bohm limit. Only diffusive acceleration at the quasi-perpendicular solar wind termination shock has a high enough acceleration rate to be the source of the anomalous component.

Original languageEnglish (US)
Pages (from-to)L41-L43
JournalAstrophysical Journal
Issue number1 PART 2
StatePublished - Jul 1 1992


  • Acceleration of particles
  • Shock waves
  • Solar wind

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


Dive into the research topics of 'Constraints on the acceleration of anomalous cosmic rays'. Together they form a unique fingerprint.

Cite this