  A multi-species Fokker-Planck model for simulating particle collisions in a
plasma is presented. The model includes various parameters that must be tuned.
Under reasonable assumptions on these parameters, the model satisfies
appropriate conservation laws, dissipates an entropy, and satisfies an
$\mathcal{H}$-Theorem. In addition, the model parameters provide the additional
flexibility that is used to match simultaneously momentum and temperature
relaxation formulas derived from the Boltzmann collision operator for a binary
mixture with Coulomb potentials. A numerical method for solving the resulting
space-homogeneous kinetic equation is presented and two examples are provided
to demonstrate the relaxation of species bulk velocities and temperatures to
their equilibrium values.
