Preacceleration of anomalous cosmic rays in the inner heliosphere

Joe Giacalone, J. Randy Jokipii, R. B. Decker, S. M. Krimigis, M. Scholer, H. Kucharek

Research output: Contribution to journalArticle

33 Citations (Scopus)

Abstract

Because of the apparent difficulty in accelerating previously unaccelerated pickup ions locally at the solar wind termination shock, a model for anomalous cosmic-ray protons is considered in which the initial acceleration of pickup ions to ∼ 10-20 MeV occurs in the inner heliosphere. These accelerated pickup ions are assumed to be accelerated either by propagating interplanetary shocks or by some other, unspecified process. Voyager 2 Low-Energy Charged Particle (LECP) observations at low energies are used to normalize their spectra. The ions are then transported to the termination shock, where they are further accelerated to anomalous cosmic-ray energies. We use a well-established transport model to simulate this process. In this model, the two-dimensional cosmic-ray transport equation is solved using the assumed (and normalized) source of energetic particles (∼0.01-20 MeV) located at 10 AU. We show that the computed spectra at higher energies (≳100 MeV) are consistent with observed anomalous cosmic-ray fluxes and suggest that interplanetary shocks, especially those in the inner heliosphere, may play an important role in the initial acceleration of pickup ions leading to anomalous cosmic rays.

Original languageEnglish (US)
Pages (from-to)471-476
Number of pages6
JournalAstrophysical Journal
Volume486
Issue number1 PART I
DOIs
StatePublished - 1997

Fingerprint

heliosphere
cosmic ray
cosmic rays
ion
interplanetary shock waves
sensors
ions
energy
shock
energetic particles
solar wind
charged particles
energetics
protons
particle

Keywords

  • Acceleration of particles
  • Cosmic rays
  • Diffusion
  • Shock waves

ASJC Scopus subject areas

  • Space and Planetary Science

Cite this

Giacalone, J., Jokipii, J. R., Decker, R. B., Krimigis, S. M., Scholer, M., & Kucharek, H. (1997). Preacceleration of anomalous cosmic rays in the inner heliosphere. Astrophysical Journal, 486(1 PART I), 471-476. https://doi.org/10.1086/304497

Preacceleration of anomalous cosmic rays in the inner heliosphere. / Giacalone, Joe; Jokipii, J. Randy; Decker, R. B.; Krimigis, S. M.; Scholer, M.; Kucharek, H.

In: Astrophysical Journal, Vol. 486, No. 1 PART I, 1997, p. 471-476.

Research output: Contribution to journalArticle

Giacalone, J, Jokipii, JR, Decker, RB, Krimigis, SM, Scholer, M & Kucharek, H 1997, 'Preacceleration of anomalous cosmic rays in the inner heliosphere', Astrophysical Journal, vol. 486, no. 1 PART I, pp. 471-476. https://doi.org/10.1086/304497
Giacalone, Joe ; Jokipii, J. Randy ; Decker, R. B. ; Krimigis, S. M. ; Scholer, M. ; Kucharek, H. / Preacceleration of anomalous cosmic rays in the inner heliosphere. In: Astrophysical Journal. 1997 ; Vol. 486, No. 1 PART I. pp. 471-476.
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