Spectral characteristics of ion emission in pinched discharges

Summary form only given, as follows. The energy-density increase in the current sheet (CS) of MA focused discharges during the CS radial implosion occurs via partially independent processes: (i) The relative increase, /spl Delta/J/J, of the amperian current density, J, on CS. (ii) The increased stretching, /spl Delta/B/sub /spl par///B/sub /spl par//, of the magnetic-field lines of the CS fine structure. Recent experiments with externally-controlled discharge parameters confirm that (i) dominates over (ii), for equal values of the relative variations of J and of B/sub /spl par//. The ion energy after pinch disintegration is the final outcome of the energy densification process addressed here. A comparison of the ion spectrum emitted from plasma focus discharges and from Z-pinch discharges where field-line stretching is minimized, is carried out from Thomson (parabola) spectrometer data. Data from a variety of gas-mixture fillings of the discharge vessels (D/sub 2/, and D/sub 2/+Ar) contribute to the clarification of the ion acceleration process and of the formation and emission of ion clusters.