  This is an early but comprehensive review of the PNP Poisson Nernst Planck
theory of ion channels. Extensive reference is made to the earlier literature.
The starting place for this theory of open channels is a theory of
electrodiffusion rather like that used previously to describe membranes. The
theory uses Poisson's equation to describe how charge on ions and the channel
protein creates electrical potential; it uses the Nernst-Planck equations to
describe migration and diffusion of ions in gradients of concentration and
electrical potential. Combined, these are also the "drift-diffusion equations"
of solid state physics, which are widely, if not universally used to describe
the flow of current and the behavior of semiconductors.
