Journal of Statistical Physics, Vol. 58, Nos. 5/6, 1990. p. 885-921.
New exact solutions to the time-dependent Lorentz gas Boltzmann equation are presented for two classes of nonequilibrium initial value problems: the decay of localized disturbances and the response to applied electric fields. These exact results are used to gain some insight into the crossover of the nonequilibrium state from the early-time kinetic regime to the late-time hydrodynamic regime.