Observation of plasma domains with fast ions and enhanced fusion in plasma-focus discharges

Abstract

Our experiments have established strong azimuthal anisotropy of fusion reaction products and fast ions ejected from the plasma during focused discharges in deuterium or a mixture of deuterium with 3He and/or 16O. The anisotropy is explained in terms of localized plasma domains with enhanced nuclear reactivity (emitting isotropically), displaced from the axial pinch region by up to 5.5 cm. The displaced domains generate and trap over 80% of the observed population of fast ions ( E i>2 MeV), produce the bulk of the 16O (d, n) 17F reactions ( E th≅ 2MeV) in the plasma, and have atomic density n⩾7×10 21cm -3. Most of the D+D and 3He+D fusion yield, which requires low ion energy E i⩽0.2 MeV), comes from the region close to the plasma-focus symmetry axis.