The stimulated Brillouin scattering for a bundle beam, which consists of several laser beams, is studied by using the three-dimensional large scale laser plasma interaction code (LAP3D). Several collective scattering, including the ray-retracing, shared ion acoustic wave, shared scattering light, are observed. These phenomena are explained in different parameters.

Finding ways to suppress stimulated Raman scattering(SRS) and stimulated Brillouin scattering(SBS) is an important subject in inertial confinement fusion(ICF). Under the typical laser fusion plasma conditions, the effects of transverse magnetic field and laser bandwidth on the suppression of SRS and SBS are studied by utilizing the particle-in-cell(PIC) program. It is found that the transverse magnetic field can significantly inhibit the autoresonance of SRS in the non-uniform plasma. The transverse magnetic field accelerates the electrons trapped in the electron plasma wave(EPW) excited by SRS, which causes the nonlinear damping and reduces the nonlinear frequency shift of the EPW, thus narrowing the autoresonance space and significantly reducing the SRS reflectivity. Based on the characteristics that SRS can be suppressed by a transverse magnetic field and the SBS growth is sensitive to the laser bandwidth, a scheme is proposed that utilizing the transverse magnetic field and the broadband laser to suppress SRS and SBS simultaneously. When the transverse magnetic field is on the order of 10 T and the bandwidth is on the order of 0.001, both of which are easy to achieve in experiments, the total reflectivity of SRS and SBS can be effectively suppressed in the ICF-related plasmas.