Current-sheet velocity oscillation and radiation emission in plasma focus discharges

Summary form only given, as follows. A phenomenon of current sheet velocity oscillation during the compression phase in plasma focus discharge has been found with a schlieren photography technique. The oscillation period has been determined as about 17 ns and coincided with the period of the simultaneously measured time derivative of the current. The same velocity behavior has been observed with magnetic probes. A microwave emission burst (in 3 cm and 10 cm bands) consisting of a sequence of very narrow (FWHM<1 ns) peaks, 17 ns apart one another, has also been observed before, during, and after the pinch. The microwave was polarized with the electric field parallel to the electrode axis. All these effects have been recorded on the same PF device (6 kJ). The origin of these oscillations can be interpreted in a few ways, e.g. as related to the electrode-plasma sheath RLC circuit, or to the j/sub s//spl times/B of the plasma current sheet, where j/sub s/ is the current density component perpendicular to the current sheet surface. The j/sub s/ is related to the current sheet velocity. These results provide the basis of our analysis.