SKYLAB XUV Observations of Densities, Thermal Structure, and Mass Motions in a Compact Flare
Abstract
The energetic limb flare of 1973 December 17 was one of the best Skylab examples of a class characterized by small volume, high energy density, and short lifetime. In the present paper the authors have studied the extensive series of slit spectra of this flare obtained with the NRL slit spectrograph on Skylab operating in the 1000 - 1945 Å range. An overview of the flare development and exposure chronology is given. Examples of the flare morphology observed in He II, Ne IV, and Mg VII are contrasted with the morphology observed in Fe XVII. Slit profiles of Fe XXI 1354 Å, O V 1371 Å, and Si IV 1403 Å are presented. The electron density is derived at selected phases from diagnostic line ratios of O IV, O V, S IV, and S V observed in the slit spectra. In the decay phase these densities are combined with the densities derived from high-temperature lines to obtain the density distribution in the flare between 105K and 6×106K. The arch structure within the 5arcsec×5arcsec kernel is resolved and an improved picture of the density spatial structure of the flare kernel is derived.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- September 1987
- DOI:
- 10.1086/165609
- Bibcode:
- 1987ApJ...320..913W
- Keywords:
-
- Solar Flares;
- Solar Spectra;
- Solar X-Rays;
- Ultraviolet Spectra;
- Electron Density (Concentration);
- Iron;
- Line Spectra;
- Spectral Line Width;
- Solar Physics;
- SUN: FLARES;
- SUN: X-RAYS;
- ULTRAVIOLET: SPECTRA