Strongly coupled large-angle stimulated Raman scattering of short laser pulse in plasma-filled capillary

Abstract

Strongly coupled large-angle stimulated Raman scattering (LA SRS) of a short intense laser pulse develops in a plane plasma-filled capillary differently than in a plasma with open boundaries. Coupling the laser pulse to a capillary seeds the LA SRS in the forward direction (scattering angle smaller than π/2) and can thus produce a high instability level in the vicinity of the entrance plane. In addition, oblique mirror reflections off capillary walls partly suppress the lateral convection of scattered radiation and increase the growth rate of the SRS under arbitrary (not too small) angle. Hence, the saturated convective gain falls with an angle much slower than in an unbounded plasma and even for the near-forward SRS can be close to that of the direct backscatter. At a large distance, the LA SRS evolution in the interior of the capillary is dominated by quasi-one-dimensional leaky modes, whose damping is related to the leakage of scattered radiation through the walls.

On the Theory of the Mandelstam–Brillouin Scattering in a Plasma Layer

“…In [13], the author noted that any multidimensional scattering problem can be reduced to a one-dimensional one and obtained an asymptotic solution for scattering in an inhomogeneous medium. Subsequently, the problems of scattering in a two-dimensional medium based on ideas of [13] were considered in [14][15][16][17][18][19][20]. Nevertheless, in the general case, the instability thresholds and increments in limited plasmas have not been calculated for an arbitrary angle of incidence of the pump wave, although the propagation of the pump wave along a long plasma column was discussed and the asymptotics of solutions realized at long times were considered.…”