Azimuthal anisotropy in the distribution of fusion products and fast ion emission in plasma focus discharges

The experiments have confirmed the existence of a pronounced azimuthal anisotropy in the ion and fusion product emission from the plasma focus pinch. The anisotropy was measured with a circular array of thin-wall Geiger-Muller counters all parallel to the plasma focus electrode axis. The counters measure the radioactivity from reaction products in the plasma deposited on, or induced by D+ ions, on thin Cu foils wrapping the detectors. The observed azimuthal anisotropy is consistent with the formation of the localized plasma domains of enhanced nuclear reactivity (PDER) displaced up to 5 cm from the PF symmetry axis. PDERs are carrying ions of energy Ed > 2 MeV (defined by threshold reactions) and have a density of about 1022/cm3 established from [fusion induced radioactivity]/[beam induced radioactivity], and the confinement time τ (= duration of hard radiation pulses)