Gas-injection experiments on a dense plasma focus

Conference · Sat Dec 31 04:00:00 EST 1994

OSTI ID:46172

Barnouin, O; Javedani, J; Del Medico, S ^[1]; Miley, G H; Bromley, B ^[2]

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1. Rockford Technology Associates, Inc., Champaign, IL (United States)
2. Fusion Studies Lab., Urbana, IL (United States)

Rockford Technology Associates, Inc. (RTA) has been doing experiments on the Dense Plasma focus (DPF) device at the Fusion Studies Laboratory of the University of Illinois. This DPF consists of four racks of five 2-{mu}F capacitors whose charge is switched onto the inner electrode of a plasma focus by four Trigatron spark gaps. The stored energy is 12.5 kJ at 25 kV. The bank is usually discharged in a static fill of H{sub 2} at {approx} 6 torr. Preliminary experiments aimed at exploring the potential of the DPF device as a magnetoplasmadynamic (MPD) thruster and as an x-ray source for lithography have investigated various alternative ways of injecting gas between the electrodes. One of those approaches consists of injecting gas from the tip of the inner electrode at a steady rate. In this operation, the DPF chamber pressure was held constant by running the vacuum pump at full throttle. This operation simulated simultaneous pulsed injection at the base insulator and electrode tip. Hydrogen was fed through a 1/16th-inch hole at a flow rate of {approx} 90 cm/s. Pulsing was then performed at 23 kV, and the corresponding variations of the current were observed using a Rogowski coil. It is found that the plasma collapses into a pinch at the same time as in conventional experiments using a static fill. The singularity in the current waveform is slightly smaller with tip injection, but its size and shape are easily reproducible. Further details and comparison of this operation with conventional pulsing will be presented.

• OSTI ID: 46172
• Report Number(s): CONF-940604--; ISBN 0-7803-2006-9
• Country of Publication: United States
• Language: English

Related Subjects

33 ADVANCED PROPULSION SYSTEMS
42 ENGINEERING
70 PLASMA PHYSICS AND FUSION TECHNOLOGY
CAPACITIVE ENERGY STORAGE EQUIPMENT
FABRICATION
GAS INJECTION
HYDROGEN
INTEGRATED CIRCUITS
ION THRUSTERS
MAGNETOHYDRODYNAMICS
PLASMA FOCUS DEVICES
PROPULSION SYSTEMS
USES
X-RAY SOURCES