Nonlinear depletion of ultrashort and relativistically strong laser pulses in an underdense plasma

Abstract

The depletion of a relativistically strong laser pulse in the course of interaction with underdense plasmas is considered. The driving mechanisms of distortion and fast depletion of the pulse due to the nonlinear plasma wake excitation are discussed. The role of the backward stimulated Raman scattering in the process of the leading front steepening is traced. Electron acceleration and heating due to plasma wave breaking are demonstrated. The evidence that the final stage of the pulse depletion can be accompanied by the formation of relativistically strong solitonlike electromagnetic modes is presented.

Nonlinear Pulse Propagation and Phase Velocity of Laser-Driven Plasma Waves

“…(4) and (5) with the initial conditions, e.g.,k(0) = 1,k ′ (0) = 0, ∂τk(0) = x ′ /2x 2 , and ∂τ a 2 (0) = −x ′ a 2 /x 2 + aa ′ /x. The rate of change of the phase velocity is given by the coupled equations (6), (10), and (17). Figure 2 shows a comparison of the rate of change of the phase velocity Eq.…”

Charged particle acceleration in nonuniform plasmas

“…2% propagates with a velocity smaller than the linear e n wave group velocity. This can be explained by the local downshift of the electromagnetic wave fresuency [7,15]. This fresuency downshift lads to the decrease of the wave phase velocity of the wake plasma seen in Fig.…”

“…The feature of the pulse that is specifically responsible for providing good conditions for particle acceleration is the sharp rise of the pulse front, Sharpening of relativistically intense pulses propagating in an underdense plasma via the backward stimulated Raman scattering process has been observed in [7] and [SI.…”

Laser guiding for GeV laser–plasma accelerators

“…Wake excitation leads to loss of laser pulse energy. The pump depletion length (the distance over which the pump loses a significant fraction of its energy) can be estimated by equating the laser pulse energy to the energy left behind in the wake (Horton & Tajima 1986;Bulanov et al 1992). In the linear limit (a 2 0 1), the pump depletion length is L pd ∼ (λ 3 p /λ 2 0 )a −2 0 , Article submitted to Royal Society whereas in the nonlinear limit (a 2 0 1), L pd ∼ (λ 3 p /λ 2 0 )a 0 .…”