ABSTRACT
The modern study of matter at extreme conditions began in the 1930s with efforts to understand the generation and transfer of fusion energy in stellar interiors. The important discoveries of this early astrophysical research include the Saha ionization law, the degenerate (Fermi-Dirac) equation of state, and the first theories of conductive and radiative heat transfer in hot matter, as well as the first understanding of thermonuclear fusion reactions. This chapter provides an overview survey of atomic processes in hot dense plasmas and attempts to identify the main phenomena which form the subject of active research in many laboratories. Laser irradiation of solid targets leads to a variety of nonequilibrium plasma phenomena, described in many articles which review target interaction experiments. In plasmas containing heavy elements, there is an important question whether nonequilibrium effects occur at high densities and coexist with dense-plasma physics.
