The abundances of elements and isotopes in the solar wind
- The Johns Hopkins University, Applied Physics Laboratory, Laurel, Maryland 20707, USA (USA)
- Physikalisches Institut, University of Bern (Switzerland)
Solar wind abundances have now been measured for eleven elements and the isotopes of the noble gases. The composition of all elements up to and including Ni, as well as most of their isotopes, should become known when new high-mass-resolution solar wind spectrometers are launched in the next decade. Aside from solar wind protons and alpha particles, which have been studied extensively since the 1960's, our information for heavier elements is limited. Nevertheless, two effects stand out. First is the enrichment of abundances of elements with low first ionizaiton potential (FIP), most likely the combined result of (a) an atom-ion separation process in the upper chromosphere, and (b) a marginal coupling of low-charge-state heavy ions to protons and alphas during the acceleration of the solar wind. Second, there is variability in the solar wind composition over a whole range of time scales. Recent measurements carried out in the Earth's magnetosheath during times that included high-speed coronal-hole-associated flows indicate a significantly lower overabundance of low FIP elements. Given the fact that the He/H ratio is remarkably constant in the coronal hole solar wind, this result suggests that both enrichment and variability are reduced in such flows. Studies by the ULYSSES spacecraft of the characteristics and composition of the least complicated solar wind, i.e., the flow emanating from the polar coronal holes, should significantly increase our understanding of coronal processes and solar wind acceleration. By combining these studies with measurements of the complete elemental and isotopic composition of the solar wind, we will be able to derive solar abundances for elements and isotopes that otherwise are poorly known.
- OSTI ID:
- 6807828
- Report Number(s):
- CONF-8808175-; CODEN: APCPC; TRN: 90-018654
- Journal Information:
- AIP Conference Proceedings (American Institute of Physics); (USA), Vol. 183:1; Conference: Symposium on the cosmic abundances of matter, Minneapolis, MN (USA), 15-17 Aug 1988; ISSN 0094-243X
- Country of Publication:
- United States
- Language:
- English
Similar Records
Solar wind ion composition and charge states
VARIATIONS IN SOLAR WIND FRACTIONATION AS SEEN BY ACE/SWICS AND THE IMPLICATIONS FOR GENESIS MISSION RESULTS
Related Subjects
GENERAL PHYSICS
SOLAR WIND
ELEMENT ABUNDANCE
ISOTOPE RATIO
CHEMICAL COMPOSITION
HELIUM
HYDROGEN
IONIZATION
MAGNETOSHEATH
MASS RESOLUTION
SOLAR CORONA
ABUNDANCE
ATMOSPHERES
ELEMENTS
FLUIDS
GASES
NONMETALS
RARE GASES
RESOLUTION
SOLAR ACTIVITY
STELLAR ATMOSPHERES
STELLAR CORONAE
640104* - Astrophysics & Cosmology- Solar Phenomena