Evidence for surface heating of wire plasmas using laser irradiated cone geometries

Introduction Cone-guided compression offers a number of advantages for the fast ignition approach to inertial fusion energy. The path of the PW laser pulse is kept free of plasma, bypassing the growth of plasma instabilities that could, potentially, prevent energy transfer to the compressed dense core plasma. The deuterium-tritium fuel is assembled close to the tip of the cone so that the fast electron beam does not have far to propagate, maximising the energy coupling from the petawatt laser pulse to the thermal energy of the compressed plasma. Recent three dimensional particle-in-cell simulations have indicated that this energy coupling may be increased by self-generated magnetic fields that act to guide lower energy electrons (that are generated spatially in the wings of the focused laser pulse) into the compressed core. Indeed, recent experiments have shown that the optical emission from rear surface in the 400 nm 600 nm wavelength range for 10 μm thick Al foils decreased in size but increased in intensity with cone attached targets.