Long-term changes in composition of solar particles implanted in extraterrestrial materialsAnalysis of lunar surface samples for elements implanted therein by solar corpuscular radiation reveals evidence for the following compositional changes over a time period between 1.5 and 3 Gyr: 50-percent decreases in the ratios He-4/Ar-36 and Xe/Ar-36; a 20-percent increase in the ratio He-3/He-4; a 3-percent increase in the ratio Ne-20/Ne-22; and a 50-percent increase in the ratio N-15/N-14. The causes of these changes are not resolved at this time but may include (1) a change in acceleration conditions of the solar wind, (2) a change in flux of solar energetic particles relative to that of the solar wind, and (3) a change in composition of the solar convective zone. There is good evidence for a long-term decrease in the solar-wind flux.
Document ID
19920064057
Acquisition Source
Legacy CDMS
Document Type
Conference Proceedings
Authors
Kerridge, J. F. (California, University Los Angeles, United States)
Signer, P. (NASA Lyndon B. Johnson Space Center Houston, TX, United States)
Wieler, R. (Zuerich Eidgenoessische Technische Hochschule, Zurich, Switzerland)
Becker, R. H. (NASA Lyndon B. Johnson Space Center Houston, TX, United States)
Pepin, R. O. (Minnesota, University Minneapolis, United States)