The effects of the nonlinear polarization in a partially stripped plasma on
the parameter processes of a strong laser are discussed. The nonlinear mod
e coupling equations of stimulated Raman scattering (SRS) are derived. The
linear instability growth rates of SRS and stimulated Brillouin scattering
(SBS) are given. When the pump wave intensity I-0 > 10(17) W/cm(2), the thi
rd order susceptibility associated with bound electrons will reduce the SRS
and SBS linear growth rate enormously. In addition, the nonlinear suscepti
bility can affect the nonlinear evolution of SRS and SBS significantly.