Viewing corotating interaction regions globally using energetic neutral atoms

J. Kóta, K. C. Hsieh, J. R. Jokipii, A. Czechowski, M. Hilchenbach

Research output: Contribution to journalArticlepeer-review

17 Scopus citations


We present model simulations to estimate the flux of 25-100 keV energetic neutral atoms (ENAs) that can be expected from charge exchange between the ion populations accelerated at corotating interaction regions and the slow neutral atoms penetrating from the local interstellar matter. The extended structure of a corotating interaction region (CIR) evolving in space is a major plasma feature in the inner heliosphere that contains a wealth of information on shock development and charged-particle acceleration. The detection of energetic neutral atoms originating from CIRs, with directional, mass, and energy resolutions, is a way to view CIRs remotely. This global view in ENAs may provide important information complementary to in situ particle and plasma and field observations. We apply a three-dimensional numerical code to model CIRs and simulate the transport of energetic particles accelerated at the forward and reverse shocks of the CIR. Our simulation results are applied to the ongoing ENA observations by the Solar and Heliospheric Observatory (SOHO) and that anticipated by Cassini. We find that a CIR origin of the ENAs detected by the high suprathermal time-of-flight sensor of the charge, element, and isotope analysis system on SOHO cannot be ruled out. Our simulations also reveal that the concentration of local interstellar He atoms focused by the Sun's gravitation contributes significantly to the production of ENAs in the inner regions of the quiet heliosphere.

Original languageEnglish (US)
Article number2000JA000413
Pages (from-to)24907-24914
Number of pages8
JournalJournal of Geophysical Research: Space Physics
Issue numberA11
StatePublished - Nov 1 2001
Externally publishedYes

ASJC Scopus subject areas

  • Geochemistry and Petrology
  • Geophysics
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science
  • Atmospheric Science
  • Astronomy and Astrophysics
  • Oceanography


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