Nuclear energy obtained from thermonuclear fusion of light nuclei is a goal to which an increasing world-wide effort is being committed. The demands on energy reserves and resources are continually increasing as ever more coun tries achieve modern industrial status. All projections agree that conventional means of energy production must be supplemented and indeed supplanted by new methods. Only the date at which the transition becomes imperative is subject to debate. The promise of fusion energy ultimately to pro vide a clean, cheap, dependable and potentially inexhaustible energy source...