Coupling between High-Frequency Plasma Waves in Laser-Plasma Interactions

Effect of electron plasma waves with relativistic phase velocity on large-angle stimulated Raman scattering of modulated short laser pulse in plasmas

“…That is, in the known 3D regime of the self-modulation of a laser pulse with a power close to the critical power for the relativistic self-modulation,'4 the laser spectrum consists of the component with the carrier frequency and the anti-Stokes component blue-shifted to the plasma frequency [the on-axis pulse structure is described approximately by the dependence (11)]. For such regime of the self-modulation instability, the numerical modelling'4 performed for a plasma and laser parameters such that w0/w = 20, , = 0.256, and icLpa3 13.5 (hence, the LA SRS of such pulse is in the weakly coupled regime and is far from the nonlinear saturation) gives the maximum amplitude of the electron density perturbation NLW 0.1 {under the parameters of modelling,'4 NLW remains less than (Wpe/Wü)'/2 0.22 [see Eq.…”

“…(10) kLW k + à7CLW , and wLw Wpe + 5wLw . In order to make a dispersion analysis of the SRS instability of the laser pulse subjected to the resonant self-modulation, we consider a laser pulse which consists of two spectral components (pump waves) shifted to the frequency and wave number of the LW EPW: ao = a1 + a2eb, (11) where a1 and a2 are the constant amplitudes of the pump waves in the region Lpuise < < 0 (Lpuise S a longitudinal pulse length) and are zero outside this interval. The laser pulse with the envelope (11) consists of the components with a carrier frequency w0 and blue-shifted (anti-Stokes) frequency w0 + wLw .…”

Diagnostics for Laser Accelerators

“…6(a), a two-frequency CO 2 laser beam produced both a "slow wave" from stimulated Raman backscatter [12] and a "fast wave" from collinear optical mixing [13] (the beatwave driven mode). The spectral components of € n e (ω,k) are [14] € n e (ω,k) = ⊕˜ n fast (ω p ,k fast ) +˜ n slow (ω slow ,k slow )…”

“…(b) Features in the plasma density fluctuation spectrum seen from the Thomson scattering setup of (a) [14]. …”

The interaction of intense subpicosecond laser pulses with underdense plasmas

“…([36], [59], [69], [50] For coupling between the forward SRS plasma wave and SBS ion acoustic wave to occur, both forward SRS and SBS must first be driven in the plasma. The regime in which these instabilities can be observed in a plasma (Le., "yo'r 2 in which forward SRS is driven lies well above that required for SBS.…”