DR, Photoionization and Opacities
Nigel R. Badnell
University of Strathclyde
Department of Physics,
Glasgow, G4 0NG, U.K.
We review methodologies for describing dielectronic recombination
(DR). We look briefly at the state-of-play of theory vs experiment.
We then discuss how to deliver DR data in a form suitable for
modelling and we review the status of the partial and total DR
database being assembled for the modelling of dynamic finite-density
plasmas. We comment on the role of fields and how modelling l-changing
collisions approximately models the dynamic part of the plasma
We also consider the inverse process of photoionization and
discuss how the same approach to DR is being used for inner-shell
photoionization and the determination of opacities in stellar
interiors. In particular, we pay attention to the role of opacity
in resolving the discrepancy between the helioseismology observations
and stellar evolution models for the position of the base of
the solar convective zone.