Numerical simulations of the laser pulse interaction with an inhomogeneous, large size, high temperature plasma are presented. The laser pulse intensity, 1016 W cm−2, plasma temperature, 5 keV, and the density scale length of 300 µm correspond to the conditions of the shock ignition scenario. It is demonstrated that after a short initial burst of backscattering, a significant part of the incident laser radiation is absorbed in the underdense plasma and the energy is transported to the dense plasma by electrons with energies 20–40 keV. The absorption mechanism is associated with a self-organized resonator and cavitation of large-amplitude plasma waves in the density range below the quarter critical density. The temporal and spectral properties of reflected light are discussed.