Fe IX lines as density indicators in coronal plasmas.
Abstract
The intensity ratios of four Fe IX lines with wavelengths between 171 A and 245 A are calculated as a function of electron density by using the collision strengths and radiative transition probabilities given by Flower (1977). Three of the line ratios are sensitive to electron density in the region above about 1 million per cu cm. The results are applied to the determination of electron density in the low solar corona from observations with the Goddard spectrometers on OSO 5 and OSO 7.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- March 1979
- DOI:
- 10.1086/156917
- Bibcode:
- 1979ApJ...228..903H
- Keywords:
-
- Electron Density Profiles;
- Iron;
- Solar Corona;
- Solar Electrons;
- Solar Spectra;
- Ultraviolet Spectra;
- Black Body Radiation;
- Far Ultraviolet Radiation;
- Ground State;
- Line Spectra;
- Particle Collisions;
- Ratios;
- Solar Spectrometers;
- Temperature Effects;
- Transition Probabilities;
- Solar Physics;
- Line Intensities:Solar Corona