  A general solution to linearized Vlasov equation for an electron
electrostatic wave in a homogeneous unmagnetized plasma is derived. The
quasi-linear diffusion coefficient resulting from this solution is a continuous
function of omega in contrast to that derived from the traditional Vlasov
treatment. The general solution is also equivalent to the Landau treatment of
the plasma normal oscillations, and hence leads to the well-known Landau
damping.
