Energy convergence for singular limits of Zakharov type systems

We prove existence and uniqueness of solutions to the Klein-Gordon-Zakharov system in the energy space H-1 x L (2) some time interval which is uniform with respect to two large parameters c and alpha. These two parameters correspond to the plasma frequency and the sound speed. In the simultaneous high-frequency and subsonic limit, we recover the nonlinear Schrodinger system at the limit. We are also able to say more when we take the limits separately.