The filamentation effect in short pulse amplification by strong-coupling stimulated Brillouin scattering

Abstract

The filamentation instability in strong-coupling stimulated Brillouin scattering (sc-SBS) amplification is investigated, and the growth rate and threshold power of filamentation are calculated. Theory and simulation results show that the filamentation instability destroys the amplified seed profile in sc-SBS amplification within a typical parameter region. An increase in the plasma density, which can increase the sc-SBS growth rate and avoid Raman scattering, exacerbates the filamentation instability. The relativistic effect is shown to be the main source of filamentation; however, introducing spatiotemporal incoherence into the seed pulse can greatly alleviate the filamentation instability.

Boosting the performance of Brillouin amplification at sub-quarter-critical densities via reduction of parasitic Raman scattering

“…Fluid/envelope models can qualitatively capture all these transverse effects, as has been demonstrated in the past (see e.g. the discussion on bow-shaped seed pulses in Trines et al [26], or the work by Li et al for filamentation [40]). However, such models may fail in the nonlinear regime of the amplification, where plasma waves can reach highamplitudes and develop sharp gradients.…”

Self-focusing/Defocusing of Hermite-Sinh-Gaussian Laser Beam in Underdense Inhomogeneous Plasmas

“…ere are a lot of non-linear phenomena in the interaction between intense laser and plasma, such as self-focusing/selfdefocusing [1], filamentation [2], stimulated Raman scattering [3] and stimulated Brillouin scattering [4]. ese nonlinearities have important effects on inertial confinement fusion [5] and laser particle accelerator [6].…”