NUKLEONIKA 2006, 51(1):79-84

STATUS OF A MEGA-JOULE SCALE PLASMA-FOCUS EXPERIMENTS

Marek Scholz1, Barbara Bieńkowska1, Michał Borowiecki1, Irena Ivanova-Stanik1, Lesław Karpiński1, Włodzimierz Stępniewski1, Marian Paduch1, Krzysztof Tomaszewski1, Marek Sadowski2, Adam Szydłowski2, Pavel Kubeš3, Josef Kravárik3

1 Institute of Plasma Physics and Laser Microfusion, 23 Hery Str., 00-908 Warsaw, P.O. Box 49, Poland
2 The Andrzej Soltan Institute for Nuclear Studies, 05-400 Otwock-Świerk, Poland
3 CTU Prague, 2 Technicka Str., 166 27 Prague, Czech Republic


This paper presents results of the recent plasma-focus (PF) experiments carried out with PF facilities, which was operated at energies ranging from 0.5 MJ to about 1 MJ. Particular attention has been paid to pinch evolution, the emission of pulsed X-ray, fast electron beams, and fusion produced neutrons. Some theoretical models of the initial breakdown, which occurs at the insulator surface, are compared. It is pointed out that modeling of the breakdown is sensitive to kinetics of ionization processes and transport coefficients. Progress in experimental studies of the axial acceleration phase is unsatisfactory. Important experimental data have been collected, but new measurements are still needed. For the radial collapse phase, it was shown that the MHD modeling is efficient until the maximum compression, but plasma instabilities require more sophisticated approaches. The pinch phase was investigated by means of different diagnostics. Fusion neutron yields were measured in different experiments, but some discrepancies in scaling must still be explained. The conclusions concern directions for further studies and optimization of large-scale high-current PF facilities.