Distinguishing galactic cosmic-ray source models with first ionization potential and volatility

J. S. George, M. E. Wiedenbeck, A. F. Barghouty, W. R. Binns, E. R. Christian, A. C. Cummings, P. L. Hink, R. A. Leske, R. A. Mewaldt, E. C. Stone, T. T. Von Rosenvinge, Nathan Eugene Yanasak

Research output: Contribution to journalArticlepeer-review

2 Scopus citations


Studies of the galactic cosmic-ray source composition reveal a pattern in the elemental abundances that may be controlled by the first ionization potential (FIP) or a closely correlated parameter, the condensation temperature (volatility). Determining the true parameter is key identifying the galactic cosmic-ray source (GCRS) material. Using data from the CRIS instrument onboard the ACE spacecraft, we examine five elements that are more volatile than other elements of similar FIP. Three of these (Na, Cu, Ge) show small deficits in their source abundances that may suggest a volatility-dependent fractionation. The source abundances of Ga and Zn (an intermediate FIP element) are consistent with either model. Possible systematic uncertainties from the cosmic-ray pathlength estimate as well as effects due to the instrumental acceptance are discussed. We also compare the GCRS composition to that observed in solar energetic particles.

Original languageEnglish (US)
Pages (from-to)779-784
Number of pages6
JournalAdvances in Space Research
Issue number4
StatePublished - 2001
Externally publishedYes

ASJC Scopus subject areas

  • Aerospace Engineering
  • Astronomy and Astrophysics
  • Geophysics
  • Atmospheric Science
  • Space and Planetary Science
  • Earth and Planetary Sciences(all)


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