Bonn 2000 – wissenschaftliches Programm
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P: Plasmaphysik
P 16: Plasmadiagnostik (Poster)
P 16.46: Poster
Mittwoch, 5. April 2000, 10:30–13:00, Aula
Diagnostics of a Laser Initiated Discharge Channel for HIF Transport — •Christoph Niemann1,2, David M. Ponce1, Simon S. Yu1, Andreas Tauschwitz3, and Dieter H.H. Hoffmann2 — 1Lawrence Berkeley National Laboratory, CA — 2TU-Darmstadt — 3GSI-Darmstadt
An alternate technique for heavy ion beam transport, from the
driver to the target, is by the use of a self-standing z-pinch
plasma channel. Experiments conducted at LBNL have produced
40 cm long stable pasma channels with a peak discharge current
of 55 kA in 7 torr nitrogen gas fill. The channels are
produced by a three step sequence, including laser preionization,
low energy prepulse and high current main discharge.
The insensitivity of the channel to MHD instabilities within
the time scale relevant for beam transport is due to the wall
stabilizing effect that the prepulse discharge creates after
hydrodynamic expansion. Here we present some of the results of
ongoing experiments geared to understand the underlying physics
of the z-pinch. Schlieren measurements show the radial propagation
of a shock wave during the prepulse discharge and suggest
indirectly the evidence of the on axis gas density depression.
For the main discharge, interferometry coupled with Faraday
rotation measurements will give a space-time mapping of the
magnetic fields and the electron density. The data will be used
to benchmark simulation codes.