Astronomy and Astrophysics – Astronomy
Scientific paper
Apr 1981
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1981mnras.195..107d&link_type=abstract
Monthly Notices of the Royal Astronomical Society, Vol. 195, p. 107-114 (1981)
Astronomy and Astrophysics
Astronomy
22
Scientific paper
The widths of optically thin EUV spectral lines formed at temperatures between ≃ 3 × 104 and 2 × 105 K in the solar transition zone are larger than expected assuming ionization equilibrium. This result has been interpreted as due to non-thermal mass motions, characterized by a parameter ξ(km s-1) In this paper we discuss observations of spectral line recorded mostly at +2 arcsec outside the limb of the north and south polar coronal holes, and compare the derived values of ξ to values deduced from spectra of quiet Sun regions. These spectra were recorded by the NRL spectrograph on Skylab (1100-2000 Å). Systematic differences in line widths between coronal holes and quiet Sun region spectra are probably no larger than 0.01 Å, for the optically thin lines used in the analysis. -sight path lengths of the emitting plasma at 2 arc sec above the limb are calculated from the intensity ratios of optically thick lines of C IV, N V, Al III, and Si IV. These ratios should be 2:1 in the optically thin limit, but they are around 1.5 at 2 arcsec above the solar limb. The derived path lengths range from ≃1000 to 5000km.
Doschek George A.
Feldman Uri
Mariska John T.
No associations
LandOfFree
Mass motions in optically thin solar transition zone lines 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 Mass motions in optically thin solar transition zone lines, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Mass motions in optically thin solar transition zone lines will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-783486