Thermonuclear fusion, an energy that is slow in coming

The routine production of energy from thermonuclear fusion machines is still far beyond our reach but step by step we follow the way to get it. This article presents the actual achievements of the 2 techniques that are used in thermonuclear fusion: the magnetic confinement whose flagship is the JET (joint European torus) and whose next step will be ITER, and the inertial confinement that is based on laser implosions, heavy ion beams or electrical pinches. Most of the inertial confinement studies made in the world are dedicated to the simulation of nuclear weapons. The physical principles of a tokamak, of the laser driven ignition and of the Z-machine in the Sandia laboratory are presented briefly. (A.C.)