Experiments on plasma focus dynamics, neutron production and ion emission

Improved diagnostic methods, such as spatially resolved Tsub(e) measurements, ten-fold interferometry (N2-laser, FWHM approximately 1ns) and a Thomson spectrometer for ions were applied to two Mather-type plasma focus devices (16kV, 40kJ; 60kV, 28kJ). In the compression phase, extremely high heating rates leading to Tsub(e) maxima of approximately 2keV were observed. These are explained by lower-hybrid drift induced turbulence. Correlations between neutron output and m=0 instability growth, in particular onset time, non-linear growth, and wavelength of the instability, were found. The neutron source is located in the vicinity of the centre electrode (Z approximately 0-40mm; r approximately 0-5mm) in decaying high-density plasma structures. High-energy ions (D+ up to 3MeV and impurity ions up to about 14 MeV) are observed. They are probably accelerated within very small (approximately <0.5mm) regions close to the centre electrode. (author)