Bright betatron radiation from direct-laser-accelerated electrons at moderate relativistic laser intensity

Direct laser acceleration (DLA) of electrons in a plasma near-critical electron density (NCD) and the associated synchrotron-like radiation are discussed for moderate relativistic intensity (normalized amplitude a0 ≤ 4.3) ps length pulse. This regime is typical kJ PW-class facilities designed high-energy-density (HED) research. In experiments at PHELIX facility, it has been demonstrated that interaction 1019 W/cm2 sub-ps pulse with sub-mm NCD results generation high-current well-directed super-ponderomotive an effective temperature ten times higher than ponderomotive potential [Rosmej et al., Plasma Phys. Controlled Fusion 62, 115024 (2020)]. Three-dimensional particle-in-cell simulations provide good agreement measured energy distribution used current work to study synchrotron from DLA-accelerated electrons. The resulting x-ray spectrum critical 5 keV reveals ultrahigh photon number 7 × 1011 1–30 range focused 20 J. Numerical betatron phase contrast imaging based on DLA process parameters presented. interest applications HED experiments, which require high flux.