Nonlinear absorption of ultrapower laser radiation by relativistic underdense plasma

The nonlinear absorption of laser radiation of relativistic intensities in the underdense plasma by a mechanism of stimulated bremsstrahlung of electrons on the ions/nuclei is investigated in the low frequency approximation. Coefficient of nonlinear inverse-bremsstrahlung absorption is studied for relativistic Maxwellian plasma at asymptotically large values of laser fields and high temperatures of electrons.