  The interaction of partially ionized plasmas with an electromagnetic field is
investigated using quantum statistical methods. A general statistical
expression for the current density of a plasma in an electromagnetic field is
presented and considered in the high field regime. Expressions for the
collisional absorption are derived and discussed. Further, partially ionized
plasmas are considered. Plasma Bloch equations for the description of
bound-free transitions are given and the absorption coefficient as well as rate
coefficients for multiphoton ionization are derived and numerical results are
presented.
