The properties of the nonlinear frequency shift (NFS) especially the fluid NFS from the harmonic generation of the ion-acoustic wave (IAW) in multi-ion species plasmas have been researched by Vlasov simulation. The pictures of the nonlinear frequency shift from harmonic generation and particles trapping are shown to explain the mechanism of NFS qualitatively. The theoretical model of the fluid NFS from harmonic generation in multi-ion species plasmas is given and the results of Vlasov simulation are consistent to the theoretical result of multi-ion species plasmas. When the wave number kλDe is small, such as kλDe = 0.1, the fluid NFS dominates in the total NFS and will reach as large as nearly 15% when the wave amplitude |eφ/Te| ∼ 0.1, which indicates that in the condition of small kλDe, the fluid NFS dominates in the saturation of stimulated Brillouin scattering especially when the nonlinear IAW amplitude is large.

Backward stimulated Raman scattering (BSRS) with Langmuir decay instability (LDI) and anti-Langmuir decay instability (ALDI or anti-LDI) has been researched by Vlasov simulation. The decay productions of anti-LDI in LDI cascade and their evolution with time are demonstrated for the first time. The BSRS reflectivity will be decreased largely through LDI cascade and ALDI in the small wave-number region. Different mechanisms to saturate BSRS in CH (or H) and C plasmas have been demonstrated. The dominant saturation mechanism of BSRS in CH (or H) plasmas is LDI cascade and ALDI. However, in C plasmas, due to very weak Landau damping of ion acoustic waves, LDI cascade will promote stimulated Brillouin scattering (SBS) excitation, then SBS will compete with BSRS and saturate BSRS in the later stage. The proportion of the hot electrons is decreased largely through LDI cascade and ALDI. These results give an effective mechanism to suppress BSRS and hot electron generation in the small wave-number region, which are of important significance in the inertial confinement fusion.

The auto-resonant behavior of ion acoustic waves (IAWs) driven by stimulated Brillouin backscattering in supersonic flowing plasmas is self-consistently investigated by Vlasov simulations. Vlasov simulations show that the peak amplitude of the auto-resonant growing IAWs in the positive flow gradient is much larger than that in the negative flow gradient, which is contrary to the previous analysis (Wang et al 2018 Plasma Phys. Control. Fusion 60 025016). It is found that the IAW phase velocity remains unchanged in supersonic flowing plasmas, which significantly influences wave-particle interaction by changing the Landau damping and the coefficient of the kinetic nonlinear frequency shift in different position. As a result, the Landau damping of IAWs in the peak region in the negative case is stronger than that in the positive case, which has never been considered before. After considering its effects on particle trapping and, particularly, Landau damping of IAWs, theoretical predictions from three-wave mode equations are consistent with results by Vlasov simulations.

The mechanism of energy transfer from 3ω pump light to stimulated Brillouin scattering (SBS) generated by 2ω pump light is proposed. The backscattering light of stimulated Raman scattering (SRS) generated by 3ω pump light can work as a seed of the SBS of 2ω pump light, which results in the increase of the latter. Adding 2ω pump light into 3ω pump light will decrease the reflectivity of SBS generated from 3ω pump light. The total reflectivity will first decrease and then increase with an increase of the ratio of 2ω light intensity to the intensity of 2ω and 3ω lights f = I 2ω0 /(I 2ω0 + I 3ω0 ), and will be controlled in a lower level when this ratio f is about 10%−20%. These results give a method to control the total reflectivity of SBS and SRS in inertial confinement fusion (ICF) by adding 2ω light into 3ω light.