Density diagnostics and inhomogeneous non-isothermal plasmas

Abstract

The problem of interpreting densities in inhomogeneous non-isothermal plasmas has been discussed. It is shown how the concepts of emission measures differential in density ζ (n) and in temperature ξ (T) can be generalised to analyse arbitrary plasmas. In the special case where surfaces of constant temperature ST and of constant density Sn coincide, the possibility of deriving the density distribution as a function of temperature has been developed, provided ξ(T) is known. It is then investigated whether and when the predicted line strength of a set of sources with different n(T) but with the same ξ(T) would be distinguishable, using measurements of density sensitive lines and an empirical model of the form n(T) α T-δ. The technique can be extended, and the model form for n(T) tested, by comparing for consistency the value of δ and ηO obtained for three or more line ratios. © 1991.