Fine structure of self-field-dominated plasma

This extension of previous experiments addresses the estimate of the energy-density lower bound from local-current lower bound and ion energy in plasma structures held together by self-consistent fields. Contact prints of plasma structures impacting on a variety of solid targets are obtained via target exposure to plasma focus discharges at powering energy levels W = 5 kJ and W = 20 kJ (D2 filling at 5 Torr). The fine structure is recorded via non-uniform distribution of etched ion tracks. Ion filters of variable thickness δ ≥ 25 microm of mylar screen out D+--ions of energy < 1.5 MeV from one type of targets. Targets of a second type (without filters) assess the energy distribution of low energy ions (E < 100 keV) with space resolution better than 1 microm: impacting D+ ions saturate dangling bonds of the surface layers of the mono-crystal target. The visualization of plasma impacted areas is achieved via successive oxidation of earlier D-saturated bonds, ions with E > 1.5 MeV are confined within filaments with sharply defined boundaries of diameter ≤ 100 microm, at a distance > 25 cm from the end-of-anode region, from which the plasma structures are ejected. An estimate of the filament current is obtained from the magnetic field magnitude in the variable spacing between target and ion filter