Accession Number:

ADA199564

Title:

Experimental Studies of Coaxial Plasma Gun Current

Descriptive Note:

Final rept. Nov 1985-Dec 1987

Corporate Author:

AIR FORCE WEAPONS LAB KIRTLAND AFB NM

Personal Author(s):

Report Date:

1988-09-01

Pagination or Media Count:

391.0

Abstract:

This investigation examines a coaxial plasma gun, its plasma sheath currents and related behavior. Plasma gun applications are determined by the plasma behavior. The PUFF capacitor bank 72 micro F, 29 nH, 120 kV drives the plasma gun using a deuterium fill gas. The gas breakdown site is isolated from the dielectricvacuum interface in the AFWL system. Two gas valves deliver gas in the system. The first delivers gas from the gun breech and the second optional valve delivers gas to the gun muzzle. Currents and voltages are measured by Rogowski coils, B-dot probes and capacitive voltage probes. Silver activation neutron detectors monitor fusion product neutrons. In the snowplow mode, the plasma sheath is thin with a sharp current rise and drop. In the deflagration mode, the plasma sheath is diffuse over a large volume. Our system operated in a transition mode between the snowplow and deflagration modes with early snowplow behavior and late deflagration behavior. Neutrons are produced in a plasma pinch at the gun muzzle, indicating snowplow behavior. The slug theory models overall gun behavior to experimental accuracy. Sheath thickness estimates show sheaths of at least 25 the gun length. Experimental results are compared to four theories for plasma sheath velocities the Alfven collisionally limited model, the Rosenbluth model, the Fishbine saturated model and a single particle drift model. Keywords Plasma guns, Plasma sources, Plasma accelerators, Plasma sheaths, Plasma jets, Coaxial geometry, Megampere currents.

Subject Categories:

  • Particle Accelerators
  • Plasma Physics and Magnetohydrodynamics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE