Ignition of a laser-fusion target by a focusing shock wave

The thermonuclear ignition by a focusing shock wave and the burning of a previously compressed spherical target are analyzed. In particular, for a target consisting of a DT mixture with a mass mroughly-equal400 μg (the initial radius of this target at a DT density rho0 = 0.1 g/cm3 is r0 = 1 mm), compressed beforehand to a density rho = 40 g/cm3, a compression velocity uroughly-equal(1.5--1.6) x 107 cm/s is required for ignition of the target by a focusing shock wave. The energy deposited in the target by the time of the flash is Eroughly-equal30 kJ, while the fusion energy released during the burning is Qroughly-equal50 MJ (if the target expands freely). In other words, the fusion gain is k = Q/E/sub las/roughly-equal1600 (since only a small fraction, approx.10%, of the laser energy is transferred to the target, the ratio of the fusion energy to that of the laser is of course much lower)