Efficient Acceleration of Electrons by Moderate-Power Femtosecond Laser Pulses

The relativistic self-trapping of a laser pulse is an efficient mechanism for the acceleration of electrons, which allows one to achieve an extreme charge of a high-energy particle beam and the corresponding conversion coefficient of laser energy. It has been shown that the compression of the femtosecond laser pulse in this regime using the innovative compression after compressor approach (CafCA) [E.A. Khazanov, S.Yu. Mironov, and G. Mourou, Phys. Usp. 62, 1096 (2019)] to extremely short durations keeping the energy of the laser beam significantly increases the efficiency of particle acceleration. This effect has been illustrated on the example of the Multitera laser facility for the project implemented at the Russian National Center for Physics and Mathematics.