Laser wakefield accelerator driven by the super-Gaussian laser beam in the focus

Abstract

The injection process is one of the most crucial attributes that determine the final properties of the electron bunch in laser wakefield accelerators. Here, a new injection method is proposed and studied via particle-in-cell simulations for the typical parameters of the bubble regime. The injection is triggered by the laser beam that reaches the super-Gaussian profile in the focus. Such a beam undergoes rapid variations in its intensity distribution during the diffraction process. If this diffraction occurs in underdense plasma, consequent changes in the bubble structure activate a localized transverse injection process. The generated electron bunch is characterized by the short duration (∼2 fs) and low transverse emittance(1 mm mrad) while maintaining relatively high charge (∼0.2 nC).

Self-focusing and defocusing phenomena of super-Gaussian laser beams in plasmas carrying density gradient

“…Owing to their larger penetration or propagation in plasma, the super-Gaussian beams are expected to generate nonlinear current in larger region of the plasma and hence, the excitation of THz radiation with very significant and tunable field. This property of these beams will also enhance the interaction length of charged particles with the wakefield [45] excited in a plasma for the particle acceleration [7,46,47]. On the other hand, a little deviation in the super-Gaussian beam profiles with a small dip in the middle of their peak intensity region (generally termed as cosh-Gaussian laser beams) have been used for the second harmonic generation in cold quantum plasma [48] and in ordinary plasma with the relativistic-ponderomotive nonlinearities in the medium [49] due to their better focusing.…”

Electron acceleration by low order axisymmetric modes of Hermite-Cosh-Gaussian laser pulses in vacuum

“…Several parameters, including the size of the laser spot, pulse duration, initial phase, and intensity, have been thoroughly examined to understand their influence on the quality and energy of accelerated particles [10,11]. In order to explore the potential of these parameters, different laser beam profiles have been utilized, such as Hermite-Gaussian [10,12], Laguerre-Gaussian [13], Bessel-Gaussian [14], and other complex profiles [15][16][17] for electron acceleration. The impact of polarization on electron acceleration has been studied, and it has been observed that a radially polarized (RP) and focused laser pulse generates a greater longitudinal component of the electric field compared to non-polarized laser pulses, which leads to an increase in electron acceleration [18].…”