5. Discussion and conclusions
In this paper the total radiative losses and the total emissivity curves have been calculated for optically thin plasmas in the temperature range -108 K using the new version of the Arcetri Spectral Code.
These two curves have been calculated using different datasets for element abundances, ion fractions, transition probabilities and adopting several values of the electron density. The comparison between the resulting curves allows to evaluate the effects of each of these parameters on the total radiative losses and the total emissivity.
Parametric fits have been determined for the results; these fits may be used for analytical solution of models for the energy balance of the emitting plasma.
The total emissivity curves resulting from the present computation have been compared also with some parametric fit of total emissivity curves found in literature. The comparison has been carried out with the parametric fit given by Landini & Monsignori Fossi 1975 and Rosner et al. 1978. The latter parametric fit has been extensively used for loop modeling throughout the years. The parametric fit given by Rosner et al. 1978, based on a detailed calculation by Raymond 1979 agrees with the present results better than 50% for temperatures smaller than K. On the contrary the too simple approximation used by Landini & Monsignori Fossi 1975 shows big differences with the present results.
© European Southern Observatory (ESO) 1999
Online publication: June 18, 1999