Chromospheric and transition region diagnostics using emission-line intensities

Details Chromospheric and transition region diagnostics using emission-line intensities Chromospheric and transition region diagnostics using emission-line intensities

Oct 1991

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1991apj...379..776a&link_type=abstract

Astrophysical Journal, Part 1 (ISSN 0004-637X), vol. 379, Oct. 1, 1991, p. 776-787.

Astronomy and Astrophysics

Astrophysics

14

Chromosphere, Emission Spectra, Solar Spectra, Spectral Line Width, Optical Thickness, Solar Magnetic Field, Temperature Gradients

Scientific paper

EUV emission-line intensities from the HRTS experiment on Spacelab 2 are analyzed to determine the causes of intensity variations from point to point on the solar surface. Chromospheric lines of O I and transition region lines of C II, Si IV, and C IV exhibit saturation effects that limit the line intensities in the brighter regions. No such effect is found in lines of C I, Fe II, or Si III. The chromospheric lines saturate because the optical thickness exceeds the thermalization depth, whereas the transition region lines saturate because of the geometry of the unresolved fine structure. The latter is assumed to consist of elongated cylinder-like features oriented along magnetic lines of force that are mainly vertical. Saturation occurs when the optical thickness along the axis of the cylinders exceeds unity. Estimates based on the observed saturation effects give fill factors for the fine structure 0.005 and 0.4 at 100,000 K and 30,000 K, respectively. The corresponding lengths of the cylinders are estimated at 1000 km and 40 km at the two temperatures.

Affiliated with

Also associated with

No associations

Rating

Chromospheric and transition region diagnostics using emission-line intensities does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Chromospheric and transition region diagnostics using emission-line intensities, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Chromospheric and transition region diagnostics using emission-line intensities will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1875283