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The Genesis SolarWind Concentrator: Flight and Post-Flight Conditions and Modeling of Instrumental Fractionation

Wiens, Roger C. and Reisenfeld, Daniel B. and Olinger, Chad and Wurz, Peter and Heber, Veronica S. and Burnett, Donald S. (2013) The Genesis SolarWind Concentrator: Flight and Post-Flight Conditions and Modeling of Instrumental Fractionation. Space Science Reviews, 175 (1-4). pp. 93-124. ISSN 0038-6308. doi:10.1007/s11214-013-9961-1.

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The Genesis mission Solar Wind Concentrator was built to enhance fluences of solar wind by an average of 20x over the 2.3 years that the mission exposed substrates to the solar wind. The Concentrator targets survived the hard landing upon return to Earth and were used to determine the isotopic composition of solar-wind—and hence solar—oxygen and nitrogen. Here we report on the flight operation of the instrument and on simulations of its performance. Concentration and fractionation patterns obtained from simulations are given for He, Li, N, O, Ne, Mg, Si, S, and Ar in SiC targets, and are compared with measured concentrations and isotope ratios for the noble gases. Carbon is also modeled for a Si target. Predicted differences in instrumental fractionation between elements are discussed. Additionally, as the Concentrator was designed only for ions ≤22 AMU, implications of analyzing elements as heavy as argon are discussed. Post-flight simulations of instrumental fractionation as a function of radial position on the targets incorporate solar-wind velocity and angular distributions measured in flight, and predict fractionation patterns for various elements and isotopes of interest. A tighter angular distribution, mostly due to better spacecraft spin stability than assumed in pre-flight modeling, results in a steeper isotopic fractionation gradient between the center and the perimeter of the targets. Using the distribution of solar-wind velocities encountered during flight, which are higher than those used in pre-flight modeling, results in elemental abundance patterns slightly less peaked at the center. Mean fractionations trend with atomic mass, with differences relative to the measured isotopes of neon of +4.1±0.9 ‰/amu for Li, between −0.4 and +2.8 ‰/amu for C, +1.9±0.7‰/amu for N, +1.3±0.4 ‰/amu for O, −7.5±0.4 ‰/amu for Mg, −8.9±0.6 ‰/amu for Si, and −22.0±0.7 ‰/amu for S (uncertainties reflect Monte Carlo statistics). The slopes of the fractionation trends depend to first order only on the relative differential mass ratio, Δm/m.

Item Type:Article
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URLURL TypeDescription
Wiens, Roger C.0000-0002-3409-7344
Reisenfeld, Daniel B.0000-0003-1874-9450
Burnett, Donald S.0000-0001-9521-8675
Additional Information:© 2013 Springer Science+Business Media Dordrecht. Received: 8 August 2012; Accepted: 22 January 2013; Published online: 19 February 2013. The authors at LANL are grateful for a grant from NASA’s Laboratory Analysis of Returned Samples (LARS) program, as well as Discovery Program office funding to the Genesis mission. The authors are also grateful to all who made possible the Concentrator experiment, including the Genesis flight. We thank the ACE SWICS instrument team and the ACE Science Center for providing the ACE data.
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Issue or Number:1-4
Record Number:CaltechAUTHORS:20150423-092914490
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Official Citation:Wiens, R., Reisenfeld, D., Olinger, C., Wurz, P., Heber, V., & Burnett, D. (2013). The Genesis Solar Wind Concentrator: Flight and Post-Flight Conditions and Modeling of Instrumental Fractionation. Space Science Reviews, 175(1-4), 93-124. doi: 10.1007/s11214-013-9961-1
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:56903
Deposited On:24 Apr 2015 22:17
Last Modified:10 Nov 2021 21:05

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