Radiative Transfer in the Fine Structures of Quiescent Prominences


1 Department of Physics,Tabriz University

2 Department of Physics,Tokai University


Abstract. In this paper, elaborating the statistical approach recently proposed by one of the present
authors (A.G.N) has been elaborated for interpretation of the spatial brightness variations of solar
quiescent prominences. The mean statistical characteristics of the LTE line radiation such as the mean
intensity and its Relative Mean Square Deviation (RelMSD) emerging from a multi-component atmosphere
with randomly varying properties are derived as the functions of the frequency within a line. The results
previously obtained are extended to encompass more realistic models when
uctuations of the observed
line intensities represent a combined e ect of variation of di erent physical and geometrical parameters
of the medium (internal energy sources, optical thickness, velocity eld, the number of structural elements
along the line of sight etc.). It is shown that the center-to-wings evolution of the RelMSD essentially
depends on the mentioned features of the atmosphere, which are responsible for the spatial variations we
observe. The obtained results are applied to the EUV-lines through SUMER spectrometer in frameworks
of the SOHO space mission. As a rule, the observed values of RelMSD in the central frequencies of the
observed lines are less than those in the wings. This points out that the observed
uctuations are mainly
due to the changes in energy sources in the prominence. It is shown that the central dispersion of the
RelMSD correlates with the characteristic temperature of a given line formation.