skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: 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, interstream, and coronal mass ejection material were obtained. While many of the 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 include noble gas (He, Ne, Ar, Kr, and Xe) isotope ratios in the bulk solar wind and in different solarwind regimes, and the nitrogen and oxygen isotope ( 18O/ 17O/ 16O) ratios 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 been analyzed to date. The regime compositions are so far ambiguous on the occurrence of the type of isotopic fractionation expected from Coulomb drag acceleration. Neon results from closed system stepped etching of bulk metallic glass have revealedmore » the nature of isotopic fractionation as a function of depth, which in lunar samples have for years deceptively suggested the presence of a separate solar component. Isotope ratios of the heavy noble gases, nitrogen, and oxygen are still in the process of being measured.« less

Authors:
 [1];  [2];  [3];  [4];  [4];  [4];  [5];  [1]
  1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  2. Geological and Planetary Sciences, Pasadena, CA (United States)
  3. Washington Univ., St. Louis, MO (United States)
  4. Isotope Geology, Zurich (Switzerland)
  5. Univ. of Montana, Missoula, MT (United States)
Publication Date:
Research Org.:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1211591
Report Number(s):
LA-UR-07-1091
DOE Contract Number:
AC52-06NA25396
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
58 GEOSCIENCES

Citation Formats

Wiens, Roger C., Burnett, D. S., Hohenberg, C. M., Meshik, A., Heber, V., Grimberg, A., Wieler, R., and Reisenfeld, D. B. Solar and solar-wind composition results from the genesis mission. United States: N. p., 2007. Web. doi:10.2172/1211591.
Wiens, Roger C., Burnett, D. S., Hohenberg, C. M., Meshik, A., Heber, V., Grimberg, A., Wieler, R., & Reisenfeld, D. B. Solar and solar-wind composition results from the genesis mission. United States. doi:10.2172/1211591.
Wiens, Roger C., Burnett, D. S., Hohenberg, C. M., Meshik, A., Heber, V., Grimberg, A., Wieler, R., and Reisenfeld, D. B. Tue . "Solar and solar-wind composition results from the genesis mission". United States. doi:10.2172/1211591. https://www.osti.gov/servlets/purl/1211591.
@article{osti_1211591,
title = {Solar and solar-wind composition results from the genesis mission},
author = {Wiens, Roger C. and Burnett, D. S. and Hohenberg, C. M. and Meshik, A. and Heber, V. and Grimberg, A. and Wieler, R. and Reisenfeld, D. B.},
abstractNote = {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, interstream, and coronal mass ejection material were obtained. While many of the 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 include noble gas (He, Ne, Ar, Kr, and Xe) isotope ratios in the bulk solar wind and in different solarwind regimes, and the nitrogen and oxygen isotope ( 18O/17O/16O) ratios 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 been analyzed to date. The regime compositions are so far ambiguous on the occurrence of the type of isotopic fractionation expected from Coulomb drag acceleration. 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 a separate solar component. Isotope ratios of the heavy noble gases, nitrogen, and oxygen are still in the process of being measured.},
doi = {10.2172/1211591},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Tue Feb 20 00:00:00 EST 2007},
month = {Tue Feb 20 00:00:00 EST 2007}
}

Technical Report:

Save / Share:
  • NASA's Genesis space mission returned samples of solar wind collected over {approx}2.3 years. We present elemental and isotopic compositions of He, Ne, and Ar analyzed in diamond-like carbon targets from the slow and fast solar wind collectors to investigate isotopic fractionation processes during solar wind formation. The solar wind provides information on the isotopic composition for most volatile elements for the solar atmosphere, the bulk Sun and hence, on the solar nebula from which it formed 4.6 Ga ago. Our data reveal a heavy isotope depletion in the slow solar wind compared to the fast wind composition by 63.1 {+-}more » 2.1 per mille for He, 4.2 {+-} 0.5 per mille amu{sup -1} for Ne and 2.6 {+-} 0.5 per mille amu{sup -1} for Ar. The three Ne isotopes suggest that isotopic fractionation processes between fast and slow solar wind are mass dependent. The He/H ratios of the collected slow and fast solar wind samples are 0.0344 and 0.0406, respectively. The inefficient Coulomb drag model reproduces the measured isotopic fractionation between fast and slow wind. Therefore, we apply this model to infer the photospheric isotopic composition of He, Ne, and Ar from our solar wind data. We also compare the isotopic composition of oxygen and nitrogen measured in the solar wind with values of early solar system condensates, probably representing solar nebula composition. We interpret the differences between these samples as being due to isotopic fractionation during solar wind formation. For both elements, the magnitude and sign of the observed differences are in good agreement with the values predicted by the inefficient Coulomb drag model.« less
  • We use Advanced Composition Explorer (ACE)/Solar Wind Ion Composition Spectrometer (SWICS) elemental composition data to compare the variations in solar wind (SW) fractionation as measured by SWICS during the last solar maximum (1999–2001), the solar minimum (2006–2009), and the period in which the Genesis spacecraft was collecting SW (late 2001—early 2004). We differentiate our analysis in terms of SW regimes (i.e., originating from interstream or coronal hole flows, or coronal mass ejecta). Abundances are normalized to the low-first ionization potential (low-FIP) ion magnesium to uncover correlations that are not apparent when normalizing to high-FIP ions. We find that relative tomore » magnesium, the other low-FIP elements are measurably fractionated, but the degree of fractionation does not vary significantly over the solar cycle. For the high-FIP ions, variation in fractionation over the solar cycle is significant: greatest for Ne/Mg and C/Mg, less so for O/Mg, and the least for He/Mg. When abundance ratios are examined as a function of SW speed, we find a strong correlation, with the remarkable observation that the degree of fractionation follows a mass-dependent trend. We discuss the implications for correcting the Genesis sample return results to photospheric abundances.« less
  • Launched on 8 August 2001, the NASA Genesis mission is now collecting samples of the solar wind in various materials, and will return those samples to Earth in 2004 for analysis. A primary science goal of Genesis is the determination of the isotopic and elemental composition of the solar atmosphere from the solar wind material returned. In particular, Genesis will provide measurements of those species that are not provided by solar and in situ observations. We know from in situ measurements that the solar wind exhibits compositional variations across different types of solar wind flows. Therefore, Genesis exposes different collectorsmore » to solar wind originating from three flow types: coronal hole, coronal mass ejection (CME), and interstream flows. Flow types are identified using in situ measurements of solar wind protons, alphas, and electrons from electrostatic analyzers carried by Genesis. The flow regime selection algorithm and subsequent collector deployment on Genesis act autonomously. We present an assessment of composition variations of O, He, and Mg ions observed by ACE/SWICS concurrent with Genesis observations, and compare these to the Genesis algorithm decisions. Not only does this serve as a test of the algorithm, the compilation of composition vs. regime will be important for comparison to the abundances determined from sample analysis at the end of the mission.« less
  • Rocket results of ion densities during the 12 November 1966 total solar eclipse are analyzed by using detailed ion chemistry models for the D and E regions. Steady-state continuity equations for the ionic species are solved to derive the ion production rates that can best explain the full-sun ion composition results. The ion production rates so derived are inserted in a set of time-dependent solutions of the continuity equation to predict the ion density distribution during the totality of the eclipse. By comparing calculated and observed ion densities during the totality the residual ion production rates were determined, from whichmore » the part that can not be accounted for by solar radiation is attributed to the precipitation of high-energy particles in the South Atlantic geomagnetic anomaly.« less