Space and time resolved observations of plasma formations and x-ray emission in a vacuum spark discharge
- Pontificia Univ. Catolica de Chile, Santiago (Chile). Facultad de Fisica
- Ecole Polytechnique, Palaiseau (France)
- CEN La Reina, Santiago (Chile)
The Vacuum Spark is a small scale device which allows the achievement of plasma conditions leading to radiative collapse on a nanosecond timescale. The authors report on the plasma formations in a Vacuum Spark operated in the hybrid mode when driven from a 1.5 Ohm coaxial pulse forming line with a maximum current of 140 kA in a 120 ns pulse. A comparatively low power Nd:YAG laser pulse incident onto the cathode initiates the discharge. The evolution of the Titanium plasma electron density and temperature is followed both in the visible and the soft X-ray part of the spectrum. The Plasma electron density dynamics are followed using a novel micro holographic interferometric technique, based on the Mach-Zehnder Interferometer, permitting a spatial resolution better than 20 {micro}m. This technique is compared with simultaneous results from image plane interferometric holograms. The probing beam is a 1 ns frequency doubled Nd:YAG laser. The hot spots are seen to form in a submillimeter pinch stemming from the incident laser focus which has a life time of about 20 ns. The hotspots are much shorter events, reaching substantially higher densities within a nanosecond of their initiation, but which involve only part of the line density of the pinch column.
- OSTI ID:
- 449483
- Report Number(s):
- CONF-960634--
- Country of Publication:
- United States
- Language:
- English
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