Electron Acceleration in the Relativistic Self-Trapping Regime of Extreme Light

— We demonstrate the possibility of using an XCELS [1] laser pulse propagating in a plasma of near-critical density in the regime of relativistic self-trapping to accelerate a large number of electrons with an energy of about 0.2 to 2 GeV with a record charge, almost up to 0.1 μC. An even greater charge is concentrated in electrons with an energy of ∼100 MeV. This opens up new prospects for using such electron bunches to produce ultra-high-brightness sources of gamma radiation and to obtain a high yield of products of photonuclear reactions and nuclear cascades.