Pump Side-scattering in Ultra-powerful Backward Raman Amplifiers

A.A. Solodov, V.M. Malkin, and N.J. Fisch

Princeton University. Plasma Physics Laboratory.

关键词: Amplification;    Seeds Backscattering;    Light Scattering;    Laser-Plasma Interactions;    70 Plasma Physics And Fusion Technology;   

DOI  :  10.2172/827678
RP-ID  :  PPPL-3928
RP-ID  :  AC02-76CH03073
RP-ID  :  827678

美国|英语

来源: UNT Digital Library

【 摘 要 】

Extremely large laser power might be obtained by compressing laser pulses through backward Raman amplification (BRA) in plasmas. Premature Raman backscattering of a laser pump by plasma noise might be suppressed by an appropriate detuning of the Raman resonance, even as the desired amplification of the seed persists with a high efficiency. In this paper, we analyze side-scattering of laser pumps by plasma noise in backward Raman amplifiers. Though its growth rate is smaller than that of backscattering, the side-scattering can nevertheless be dangerous, because of a longer path of side-scattered pulses in plasmas and because of an angular dependence of the Raman resonance detuning. We show that side-scattering of laser pumps by plasma noise in BRA might be suppressed to a tolerable level at all angles by an appropriate combination of two detuning mechanisms associated with plasma density gradient and pump chirp.