The gradient of galactic cosmic rays at the solar-wind termination shock

J. Randy Jokipii, J. Kóta, E. Merényi

Research output: Contribution to journalArticle

48 Citations (Scopus)

Abstract

We report on a study of the expected spatial variation of the galactic cosmic-ray intensity in the outer heliosphere, in the vicinity of the solar-wind termination shock. Model simulations which contain all of the transport effects, including drifts, predict that the radial gradients change abruptly at the shock, and that the nature of the effect varies significantly with particle energy. At low energies, the radial gradient changes abruptly from a lower value inside the shock to a higher value outside, whereas at high energies, the higher value of the gradient is inside the shock. This effect, which is a consequence of the matching conditions at the shock and is closely related to diffusive shock acceleration, is qualitatively the same for both helisopheric magnetic polarity states and remains much the same in one-dimensional, two-dimensional, and three-dimensional models. Hence drifts do not change the nature of this phenomenon, although they change it quantitatively. The effect is, of course, not present in the absence of a terminal shock and may prove to be an important diagnostic tool for the study of the termination of the solar wind.

Original languageEnglish (US)
Pages (from-to)782-786
Number of pages5
JournalAstrophysical Journal
Volume405
Issue number2
StatePublished - Mar 10 1993

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cosmic ray
solar wind
shock
gradients
energy
spatial variation
heliosphere
three dimensional models
effect
particle energy
polarity
simulation

Keywords

  • Cosmic rays
  • Shock waves
  • Solar wind

ASJC Scopus subject areas

  • Space and Planetary Science

Cite this

The gradient of galactic cosmic rays at the solar-wind termination shock. / Jokipii, J. Randy; Kóta, J.; Merényi, E.

In: Astrophysical Journal, Vol. 405, No. 2, 10.03.1993, p. 782-786.

Research output: Contribution to journalArticle

Jokipii, J. Randy ; Kóta, J. ; Merényi, E. / The gradient of galactic cosmic rays at the solar-wind termination shock. In: Astrophysical Journal. 1993 ; Vol. 405, No. 2. pp. 782-786.
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