  The problems of high linear conductivity in an electric field, as well as
nonlinear conductivity, are considered for plasma-like systems.
  First, we recall several observations of nonlinear fast charge transport in
dusty plasma, molecular chains, lattices, conducting polymers and semiconductor
layers. Exploring the role of noise we introduce the generalized Fokker-Planck
equation.
  Second, one-dimensional models are considered on the basis of the
Fokker-Planck equation with active and passive velocity-dependent friction
including an external electrical field. On this basis it is possible to find
the linear and nonlinear conductivities for electrons and other charged
particles in a homogeneous external field. It is shown that the velocity
dependence of the friction coefficient can lead to an essential increase of the
electron average velocity and the corresponding conductivity in comparison with
the usual model of constant friction, which is described by the Drude-type
conductivity. Applications including novel forms of controlled charge transfer
and non-Ohmic conductance are discussed.
