Electron and ion energies over 100 keV in a dense plasma focus: results, theory and prospects

Summary form only given, as follows. Controlled fusion with hydrogen-boron-11 is an extremely attractive potential energy source. This fuel generates nearly all its energy in the form of charged particles, not neutrons, thus minimizing or eliminating induced radioactivity. It also allows direct conversion of charged-particle energy to electric power, without the expensive intermediate step of generating steam for turbines. But fusion with such fuel requires average electron and ion energies above 100 keV in a dense plasma. Recent experiments have met this requirement (using fill gases other than pB11) and have demonstrated electron and ion energies over 100 keV in a dense plasma focus device which is compact and inexpensive. This was achieved in plasma hot spots or plasmoids that, in the best results, had a density-confinement-time-energy product of 5.5 /spl times/ 10/sup 15/ keV sec/ cm/sup 3/, a record for any fusion experiment and a factor of ten above the best achieved in the much larger tokamak experiments. I review these results and compare them with theoretical predictions. The previously developed theory is largely confirmed, and a more detailed model is elaborated. I then outline the steps needed to achieve break-even operation.