A method of analysing the emission lines of solar prominences
Abstract
A new method of analysing the emission spectrum of solar prominences is presented, in which the source function is allowed to vary with optical depth. Least-squares fitting of the observed profile determines simultaneously the optical depth τ 0, the Doppler width Δλ D and the factor α characterising the variation of the source function. This method is applied to the early Balmer lines in ten prominences of Ref. [1]. The results show that the source function of the self-reversed H α line increases towards the centre of the prominence, the value at the centre is 1.2-2.5 times the value at the edge. Neglect of this variation will give too large values of τ 0. The degree of attenuation by selfabsorption also depends on this variation. Discussion of the variation gives support to the view that the main exciting mechanism in solar prominences is the scattering of the incident radiation.
- Publication:
-
Chinese Astronomy and Astrophysics
- Pub Date:
- December 1983
- DOI:
- 10.1016/0275-1062(83)90006-1
- Bibcode:
- 1983ChA&A...7..269W