Parametric studies in a small plasma focus device

Summary form only given. Very high temperature and density plasmas can be produced in modest size plasma focus devices at the kJ level. Apart from basic scientific interests, such plasmas are of fundamental importance in the production of X-rays and particle beams for a wide range of technological applications. Much of the scaling parameters on the plasma focus have been evaluated, though many questions still remain. The modest cost and simple construction allows easy modification to the device and the discharge parameters. In this paper we report on a small plasma focus device, which is set-up to investigate the effect of some of these modifications on the plasma, with detailed experimental diagnostics. The device is a Mather type plasma focus, which is powered by a 9 /spl mu/f capacitor bank, operating at 30 kV. The discharge is formed between a hollowed anode and six symmetrically arranged cathode rods. An auxiliary circuit has been implemented in order to enhance initial breakdown and current sheath formation. An extensive array of diagnostics has been implemented, which includes voltage and current probes in the external circuit. An array of small magnetic probes located along the cathode rods is used to study the current sheath structure during the run down phase of the discharge. The probes are shielded behind the cathode rods, and allow non-perturbing measurements to be made. An array of filtered PIN diodes located side and end on, is used to study the electron beam formation and the plasma emission. These time resolved observations are correlated with spaced resolved measurements, using a multi-pinhole X-ray camera. Space resolved visible spectroscopy is used to investigate the plasma dynamics during the compression phase. Time resolved visible light imaging is used to characterize the pinch phase of the discharge.