Spacecraft Measurements of the Elemental and Isotopic Composition of Solar Energetic Particles
- Creators
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Mewaldt, R. A.
Abstract
Within the past few years, instruments flown on satellites and space probes have made significant progress in measuring the elemental and isotopic composition of energetic heavy nuclei accelerated in solar flares. This paper discusses these new observations, focusing on: (1) the energy dependence of the elemental composition at energies ≥ 1 Me V/nucleon; (2) flare to flare variations in the composition; and (3) comparisons of the average solar particle abundances (2 ≤ Z ≤ 28) with other measures of the solar composition, including photospheric, coronal, and solar wind observations. These comparisons have led to the suggestion that solar flares sample the composition of the corona. Isotopic measurements of heavy solar flare nuclei have recently added a new dimension to these studies. In particular, the isotopic composition of solar flare neon has been found to be significantly different from that measured in the solar wind, but consistent with the meteoritic component neon-A.
Additional Information
This work has benefited greatly from suggestions and comments by my colleagues at Caltech, including W. R. Cook, J. D. Spalding, E. C. Stone, and R. E. Vogt. I also acknowledge helpful discussions with G. M. Mason, R. E. McGuire, and W. R. Webber. I am grateful to the following for providing experimental data prior to publication: W. R. Cook (CRS experiments on Voyager 1 and 2); D. C. Hamilton and G. Gloeckler (LECP experiments on Voyager 1 and 2); G. M. Mason (University of Maryland/Max-Planck-Insitut experiment on IMP-8); and R. E. McGuire (Goddard Space Flight Center experiment on IMP-7 and 8). This work was supported in part by NASA under Contract NAS5-20721 and grant NGR 05-002-160.Additional details
- Eprint ID
- 45018
- Resolver ID
- CaltechAUTHORS:20140417-140336777
- NAS5-20721
- NASA
- NGR 05-002-160
- NASA
- Created
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2014-04-25Created from EPrint's datestamp field
- Updated
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2019-11-22Created from EPrint's last_modified field
- Caltech groups
- Space Radiation Laboratory
- Series Name
- Geochimica et cosmochimica acta. Supplement ; 13
- Other Numbering System Name
- Space Radiation Laboratory
- Other Numbering System Identifier
- 1980-01