Abstract: In the invention, first a relatively large mass is accelerated to a few 10 km/sec and then used to implode and compress a dense magnetized plasma confined inside a small cavity. In the proposed invention the dense plasma shall consist of thermonuclear material, as for example DT, and shall reach upon compression the temperature for thermonuclear ignition. The magnetized plasma is thereby permitted to be preheated by a laser or particle beam or a gas discharge to reduce the required compression to reach thermonuclear ignition. After having reached the ignition temperature the plasma undergoes a thermonuclear burn excursion, greatly increasing its energy content. During this excursion a small window in the wall of the chamber confining the burning plasma breaks open releasing a large amount of the energy within the cavity in the form of black body radiation and shock waves.