C 4 fluxes from the sun as a star and the correlation with magnetic flux
Abstract
A total of 144 C 4 wavelength 1548 SMM-UVSP spectroheliograms of solar plages were analyzed, some of which are series of exposures of the same region on the same day. Also analyzed were C 4 wavelength 1551 rasters of plages and C 4 1548 rasters of the quiet sun. The sample contains data on 17 different plages, observed on 50 different days. The center-to-limb variations of the active regions show that the optical thickness effects in the C 4 wavelength 1548 line can be neglected in the conversion from intensity to flux density. As expected for the nearly optically thin situation, the C 4 1548 line is twice as bright as the C 4 wavelength 1551 line. The average C 4 wavelength 1548 flux density for a quiet is 2700 erg/cm/s and, with surprisingly little scatter, 18,000 erg/cm/s for plages. The intensity histograms of rasters obtained at disk centers can be separated into characteristic plage and quiet-sun contributions with variable relative filling factors. The disk-averaged flux density in the C 4 doublet and the disk-averaged magnitude of the magnetic flux density are related. The relationship between the C 4 and magnetic flux densities for spatially resolved data is inferred to be almost the same, with only an additional factor of order unity in the constant of proportionality.
- Publication:
-
Final Report Joint Inst. for Lab. Astrophysics
- Pub Date:
- August 1988
- Bibcode:
- 1988jila.reptQ....S
- Keywords:
-
- Distribution Functions;
- Faculae;
- Magnetic Flux;
- Spectrum Analysis;
- Line Spectra;
- Solar Maximum Mission;
- Spectroheliographs;
- Ultraviolet Spectroscopy;
- X Ray Spectra;
- Solar Physics