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Published June 2007 | public
Journal Article

Solar and Solar-Wind Composition Results from the Genesis Mission

Abstract

The Genesis mission returned samples of solar wind to Earth in September 2004 for ground-based analyses of solar-wind composition, particularly for isotope ratios. Substrates, consisting mostly of high-purity semiconductor materials, were exposed to the solar wind at L1 from December 2001 to April 2004. In addition to a bulk sample of the solar wind, separate samples of coronal hole (CH), interstream (IS), and coronal mass ejection material were obtained. Although many substrates were broken upon landing due to the failure to deploy the parachute, a number of results have been obtained, and most of the primary science objectives will likely be met. These objectives include He, Ne, Ar, Kr, and Xe isotope ratios in the bulk solar wind and in different solar-wind regimes, and ^(15)N/^(14)N and ^(18)O/^(17)O/^(16)O to high precision. The greatest successes to date have been with the noble gases. Light noble gases from bulk solar wind and separate solar-wind regime samples have now been analyzed. Helium results show clear evidence of isotopic fractionation between CH and IS samples, consistent with simplistic Coulomb drag theory predictions of fractionation between the photosphere and different solar-wind regimes, though fractionation by wave heating is also a possible explanation. Neon results from closed system stepped etching of bulk metallic glass have revealed the nature of isotopic fractionation as a function of depth, which in lunar samples have for years deceptively suggested the presence of an additional, energetic component in solar wind trapped in lunar grains and meteorites. Isotope ratios of the heavy noble gases, nitrogen, and oxygen are in the process of being measured.

Additional Information

© 2007 Springer Science+Business Media B.V. Received: 21 February 2007; Accepted: 29 May 2007; Published online: 3 August 2007. We thank the NASA Discovery Mission program, the NASA Jet Propulsion Laboratory, and Lockheed-Martin Astronautics, for their support of the Genesis mission. Thousands of people contributed to the mission, and our thanks also go to all of them. We also thank the organizers of this ISSI symposium.

Additional details

Created:
August 22, 2023
Modified:
October 20, 2023