Fe XII Line Ratios in Solar Flares
Abstract
Relative level populations and the density-sensitive emission-line ratios R1 = I(186.87 A)/I(193.51 A), R2 = I(196.64 A)/I(193.51 A), and R3 = I(191.05 A/I(193.51 A) are derived using the recent R-matrix calculations of electron impact excitation rates for Fe XII over a wide range of electron densities (10 to the 9th - 10 to the 12th/cu cm) and at an electron temperature of 1.5 x 10 to the 6th K. These results are applied to solar active region and flare spectra obtained by the Naval Research Laboratory's S082A slitless spectrograph on board Skylab. Excellent agreement is found with observations. The electron densities deduced from Fe XII line ratios are also in agreement with those determined from Fe XIII and Fe XIV.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- March 1991
- DOI:
- 10.1086/169786
- Bibcode:
- 1991ApJ...369..567T
- Keywords:
-
- Line Spectra;
- Metallicity;
- Solar Flares;
- Solar Spectra;
- X Ray Spectra;
- Atomic Energy Levels;
- Emission Spectra;
- Iron;
- Skylab Program;
- Solar Electrons;
- Solar Physics;
- ATOMIC PROCESSES;
- SUN: FLARES;
- SUN: SPECTRA;
- X-RAYS: SPECTRA