Experimental and theoretical investigation of electron beams generated by a dense plasma focus

The first direct measurements of the current and energy spectrum of an electron beam generated by a dense plasma focus are reported. A significant fraction of the measured spectra were found to have a bump on the high energy tail and hence did not follow a simple power law. The first simultaneous measurement of the DPF ion and electron beam energy spectra is also reported and indicates that the two have the same power law dependence, within experimental error. The main bank current was measured with a Rogowski coil, the beam current was measured with a Faraday cup, and a magnetic spectrometer was used to determine the time integrated beam energy spectrum. New calculations are presented that give the exact high frequency response of a Rogowhki coil for arbitrary terminating impedance, which are useful for interpreting Rogowski coil signals. Calculations that have led to improvements in the design of a commonly used high current electron beam Faraday cup are also reported, along with the improved design that was used for the measurements. A one-dimensional code (DPFR) was written to model the collapse phase and beam production of the dense plasma focus. DPFR solves the two fluid-Maxwell-circuit equations for a high density, z-pinch type plasma in radial geometry, and includes both classical and anomalous transport coefficients