  The coupling mechanism between crossed beams energy transfer and stimulated
Brillouin scattering in homogeneous plasmas are studied by theoretical
analysis, fluid simulations and particle in cell(PIC) simulations. The
numerical models of laser plasma instabilities are constructed by solving
coupling equations with Schodinger equations form, and the fluid simulation
results are confirmed by fluid theory and PIC simulations.In the parameter
regime when the pump depletion does not occur in CBET and the reflectivity of
SBS is lower than 1%, SBS will be affected by CBET, the CBET energy gain will
still agree with theoretical predications. However, In the parameter regime
when the pump depletion does occur in CBET and the reflectivity of SBS is
higher than 1%, the CBET spatial gain will be reduced by the interaction of
CBET and SBS, and the huge difference of SBS reflectivity for two crossed laser
beams is observed.In the PIC simulations, we found that lower ZTe=Ti will
significantly reduce the interaction between CBET and SBS (Z is the ion charge,
Teis the electron temperature, Ti is the ion temperature).
