Inhibition of stimulated Raman scattering due to the excitation of stimulated Brillouin scattering

• Published in: Physics of plasmas 2017-09, Vol.24 (9), p.92116
• Main Authors: Zhao, Yao, Yu, Lu-Le, Weng, Su-Ming, Ren, Chuang, Liu, Chuan-Sheng, Sheng, Zheng-Ming
• Format: Article
• Language: English
• Subjects: Computer simulation; Coupling; Debye length; Langmuir waves; Mathematical models; Particle in cell technique; Plasma; Plasma density; Plasma heating; Plasma physics; Plasmas (physics); Raman spectra; Saturation
• ISSN: 1070-664X; 1089-7674
• DOI: 10.1063/1.5004689

The nonlinear coupling between stimulated Raman scattering (SRS) and stimulated Brillouin scattering (SBS) of intense laser in underdense plasma is studied theoretically and numerically. Based upon the fluid model, their coupling equations are derived, and a threshold condition of plasma density perturbations due to SBS for the inhibition of SRS is given. Particle-in-cell simulations show that this condition can be achieved easily by SBS in the so-called fluid regime with k L λ D < 0.15 , where kL is the Langmuir wave number and λD is the Debye length [Kline et al., Phys. Plasmas 13, 055906 (2006)]. SBS can reduce the saturation level of SRS and the temperature of electrons in both homogeneous and inhomogeneous plasma. Numerical simulations also show that this reduced SRS saturation is retained even if the fluid regime condition mentioned above is violated at a later time due to plasma heating.