Towards inertial thermonuclear fusion with shock ignition

The principle of shock ignition is to decouple the ignition phase from the compression phase. During the implosion, a supplementary shock is generated by means of a laser beam that focuses on the center of the target in order to generate the hydrodynamics conditions required for the target ignition. The supplementary shock creates a non isobar situation where the pressure in the hot spot is higher than the pressure in the cold deuterium-tritium medium. The ignition threshold depends on the ratio of these pressures: the higher the hot spot pressure, the easier the ignition. The shock is generated by a few hundred picosecond long laser impulse. Various targets more or less far from the ignition threshold have been ignited by shock. (A.C.)