High efficiency of laser energy conversion with cavity pressure acceleration

Cavity Pressure Acceleration (CPA) is a technique for accelerating dense plasma streams by utilizing laser-generated plasma pressure within a spatially confined region. This approach has been proposed as an alternative to the classical ablative acceleration of plasma. Initially, the primary goal of this approach was to create a dense plasma stream (a theoretical macroparticle delivering energy/momentum) suitable for experiments related to Impact Fast Ignition. In recent experimental sessions, we used targets equipped with cavities lined with deuterated polyethylene ([Formula: see text]) foils and powder. These targets were irradiated with a [Formula: see text] PALS sub-kilojoule, low-contrast laser beam ([Formula: see text]), focused to an intensity of [Formula: see text] within a [Formula: see text] pulse. The scheme has proven to be highly efficient in converting laser energy into high-energy interaction products, such as high-density plasma streams and protons. We observed neutron yields among the highest achieved to date in Deuterium-Deuterium laser-induced experiments, even when compared to facilities with lasers operating at significantly higher energies and intensities. 1D hydrodynamic code used to simulate plasma parameters in the targets confirmed the high potential of the method, regardless of the driving laser wavelength.