Collisional-radiative modeling with multitemperature thermodynamic models

Abstract

The effect of the form of the law of mass-action relation used for detailed balancing in collisional-radiative (C-R) modeling is discussed and compared for various models. Details of C-R modeling with the generalized multithermal equilibrium (GMTE) thermodynamic model are presented. The results show that the asymptote for upper-level departure coefficients is not unity if T e ≠ T g and that upper-level distribution temperatures are not in general equal to T e. The criteria for regions of recombining and ionizing plasmas are identified and stability effects are discussed. A radiation absorption factor α f is introduced to describe nonlocal aspects of radiative transfer. This effect is very important in strong gradients and shows the reason for excited level distributions found at the edges of arcs and jets.