Fast ions scattering in a fixed background of electrons. The kinetic
equation for the ions is

where *v*_{t}^{2}=*T*_{e}/*m*_{i}. Treat only the one-dimensional case.

Chapman Engskog procedure gives a fluid equation
for this system in the limit . The zeroth- and
first-order distributions are

The resulting fluid equation is a simple diffusion equation

There is only one fluid equation since the collision operator only
conserves density. This simple diffusion equation also has an analytic
solution in terms of Green's functions.

Scheme involves solving eqs. (4) and (7)
simultaneously. Number conservation for the combined system gives

and transfer is implemented with

Wed Nov 26 10:29:07 EST 1997