Abundance of Iron Ions in the Solar Wind
Abstract
For a period of 4 yr near the maximum of solar cycle 21 iron and helium fluxes were measured in the solar wind. The ratio of the summed fluxes from 45,000 spectra is 400 (+50 percent, -30 percent) which is approximately 5 times lower than estimates of the solar surface value. This difference is attributed to the difference of first ionization potentials between the two elements, which leads to a preferential feeding of iron (with a lower ionization potential) into the coronal plasma, whereas helium has a tendency to remain below as a neutral species. A marked increase of the He/Fe ratio is observed in the driver gas following interplanetary shocks. Marginal depletions of helium relative to iron are found at the sector boundaries of the interplanetary magnetic field.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- June 1988
- DOI:
- 10.1086/166440
- Bibcode:
- 1988ApJ...329..956S
- Keywords:
-
- Abundance;
- Cosmochemistry;
- Iron;
- Metal Ions;
- Solar Wind;
- Helium;
- Interplanetary Medium;
- Ionization Potentials;
- Metallicity;
- Shock Wave Propagation;
- Solar Physics;
- INTERPLANETARY MEDIUM;
- SUN: ABUNDANCES;
- SUN: SOLAR WIND