  Higher intensity of strong-coupling stimulated Brillouin scattering (SC-SBS)
amplification is achieved by supplementary Raman amplification. In the new
scheme, a Raman pump laser first amplifies the seed pulse in the homogeneous
plasma, then a SC-SBS pump laser continues the amplification in the
inhomogeneous plasma in order to suppress the spontaneous instability of pump
lasers. The intensity of seed laser gets higher and the duration of seed laser
gets shorter than that in the pure SC-SBS scheme with the same incident energy,
while the energy conversion effciency is not significantly reduced. We also
found that the SC-SBS amplification is seeded by the \pi pulse of Raman
amplification. The results obtained from envelope coupling equations, Vlasov
simulations and two-dimensional particle-in-cell(PIC) simulations agree with
each other. This scheme is a simple and effective way to improve the SC-SBS
amplification and is easy to implement in experiments.
