Analysis of Extreme Ultraviolet Spectroheliograms of Solar Prominences
Abstract
The optical depth at the head of the Lyman continuum, τH, is determined at a number of positions in three hedgerow prominences using spectroheliograms (5″ × 5″ resolution) of C IIIλ 977, LC λ896, and O IV λ554 observed with the Harvard experiment on Skylab. At heights greater than 10″ above the limb the maximum value of τH is 30 to 50, which occurs at the central part of the prominences. For one of the prominences the determination of τH is found to be consistent with data from spectroheliograms of Mg X λ625. The degree of ionization of hydrogen is estimated from the intensity of LC λ896 at τH ≫ 1. In the central part of a model prominence NP/NHI≤1.9 for a reasonable range of the electron densities, where NP and NHI are the proton density and the neutral hydrogen density, respectively.
- Publication:
-
Solar Physics
- Pub Date:
- February 1981
- DOI:
- 10.1007/BF00149997
- Bibcode:
- 1981SoPh...69..313K
- Keywords:
-
- Extreme Ultraviolet Radiation;
- Lyman Spectra;
- Optical Thickness;
- Solar Prominences;
- Solar Radiation;
- Spectroheliographs;
- Calcium;
- Continuous Spectra;
- Electron Density (Concentration);
- Gas Density;
- Hydrogen;
- Line Spectra;
- Magnesium;
- Neutral Gases;
- Oxygen;
- Skylab Program;
- Solar Limb;
- Solar Spectra;
- Solar Physics;
- Hydrogen;
- Optical Depth;
- Proton Density;
- Reasonable Range;
- Neutral Hydrogen