Tailoring the laser pulse shape to improve the quality of the self-injected electron beam in laser wakefield acceleration

Abstract

In laser wakefield acceleration, tailoring the shape of the laser pulse is one way of influencing the laser-plasma interaction and, therefore, of improving the quality of the self-injected electron beam in the bubble regime. Using three-dimensional particle-in-cell simulations, the evolution dynamics of the laser pulse and the quality of the self-injected beam, for a Gaussian pulse, a positive skew pulse (i.e., one with sharp rise and slow fall), and a negative skew pulse (i.e., one with a slow rise and sharp fall) are studied. It is observed that with a negative skew laser pulse there is a substantial improvement in the emittance (by around a factor of two), and a modest improvement in the energy-spread, compared to Gaussian as well as positive skew pulses. However, the injected charge is less in the negative skew pulse compared to the other two. It is also found that there is an optimal propagation distance that gives the best beam quality; beyond this distance, though the energy increases, the beam quality deteriorates, but this deterioration is least for the negative skew pulse. Thus, the negative skew pulse gives an improvement in terms of beam quality (emittance and energy spread) over what one can get with a Gaussian or positive skew pulse. In part, this is because of the lesser injected charge, and the strong suppression of continuous injection for the negative skew pulse. V C 2013 American Institute of Physics. [http://dx.

High brightness electron beams from density transition laser wakefield acceleration for short-wavelength free-electron lasers

“…Several remedies have been suggested to address this issue, such as working just above the injection threshold, optimizing laser parameters such as pulse length and spotsize and tailoring the laser pulse shape [17,18]. These do improve the beam quality to some extent, producing an energy spread of around 3%.…”

Effect of chirp on self-modulation and laser wakefield electron acceleration in the regime of quasimonoenergetic electron beam generation

“…Therefore, controlling the FRS and the wakefields is essential for controlling the charge, energy, and quality of the electron beam in this regime. It has been suggested that by introducing a chirp in the laser pulse, the growth of FRS can be controlled [21][22][23] along with the wakefield amplitude and the electron beam parameters in the laser wakefield electron acceleration [24][25][26][27]. However, there are only a few experimental studies on the effect of frequency chirped laser pulses on electron acceleration.…”

Large-scale magnetic field generation by asymmetric laser-pulse interactions with a plasma in low-intensity regime

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