Laser-plasma injector of an ultrashort electron bunch

We report the results of numerical particle-in-cell (PIC) simulation of the generation of an electron bunch by a laser pulse upon interaction with a rarefied gas target. It is shown that the use of the electron self-injection mechanism during the breaking of a wake wave of a laser pulse propagating along an ascending slope of the plasma target density makes it possible to obtain subfemtosecond electron bunches with a charge of hundreds of pC and an electron energy of hundreds of MeV. The considered mechanism of the formation of short bunches is the basis for the development of the injector.