N E Andreev

Study of the plasma wave excited by intense femtosecond laser pulses in a dielectric capillary

Laser wakefield in a gas-filled capillary driven by a 1-TW femtosecond Ti:Sa laser pulse is studied experimentally by observing driving pulse spectrum modifications, which are caused by the combined action of the optical field ionization and the plasma density oscillations. Good agreement between the results of extensive numerical simulations and the experimental data allows us to estimate the accelerating gradients in the wake, which range from 5 to 10 MV/cm for typical experimental conditions.

Laser acceleration of electrons in two-dimensionally inhomogeneous plasma at the boundary of a metal foil

The electron acceleration mechanism associated with the generation of a plasma wave due to self-modulation instability of laser radiation in a subcritical plasma produced by a laser prepulse coming 10 ns before the arrival of the main intense femtosecond pulse is considered. Three-dimensional particle-in-cell simulations of the interaction of laser radiation with two-dimensionally inhomogeneous subcritical plasma have shown that, for a sufficiently strong plasma inhomogeneity and a sharp front of the laser pulse, efficient plasma wave excitation, electron trapping, and generation of collimated electron beams with energies on the order of 0.2–0.5 MeV can occur. The simulation results agree with experiments on the generation of collimated beams of accelerated electrons from metal targets irradiated by intense femtosecond laser pulses.

Optically produced collimated quasimonoenergetic electron beams for laser-plasma acceleration

Plasma-based electron accelerators offer a promising way in the development of the particle acceleration techniques. Acceleration gradients achievable in a laser wakefield are several orders of magnitude higher than in conventional electron accelerators, paving the way to table top electron accelerators suitable for various applications in science, medicine, and diagnostics. One of the key problems in the laser-wakefield electron acceleration is the problem of injection of electrons in a plasma wave. At high laser intensity (I>1018 W/cm2) excited wakefield amplitude can be sufficient to trap electrons from cold background plasma, however in this regime the acceleration is a highly nonlinear process leading to high instability of resulting energy, charge and direction. Many attempts have been made to make the process more reliable, however the problem has not been solved yet. The trapping issue is especially crucial when the excitation of a plasma wake occurs in more stable and reproducible linear regime. In the present work we have investigated experimentally generation of collimated quasimonoenergetic bunches of electrons by focusing intense femtosecond laser radiation on the edge of aluminum foil which can be further used for injection into a laser produced plasma wake.