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Title: Compact toroid formation, compression, and acceleration

Journal Article · · Physics of Fluids B; (United States)
DOI:https://doi.org/10.1063/1.860681· OSTI ID:7369133
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  1. High Energy Plasma Division, Phillips Laboratory, Kirtland AFB, New Mexico 87117 (United States)
  2. Physical Sciences Inc., Alexandria, Virginia 22314 (United States)
  3. Maxwell Laboratories, Inc., Albuquerque, New Mexico 87106 (United States)

Research on forming, compressing, and accelerating milligram-range compact toroids using a meter diameter, two-stage, puffed gas, magnetic field embedded coaxial plasma gun is described. The compact toroids that are studied are similar to spheromaks, but they are threaded by an inner conductor. This research effort, named MARAUDER (Magnetically Accelerated Ring to Achieve Ultra-high Directed Energy and Radiation), is not a magnetic confinement fusion program like most spheromak efforts. Rather, the ultimate goal of the present program is to compress toroids to high mass density and magnetic field intensity, and to accelerate the toroids to high speed. There are a variety of applications for compressed, accelerated toroids including fast opening switches, x-radiation production, radio frequency (rf) compression, as well as charge-neutral ion beam and inertial confinement fusion studies. Experiments performed to date to form and accelerate toroids have been diagnosed with magnetic probe arrays, laser interferometry, time and space resolved optical spectroscopy, and fast photography. Parts of the experiment have been designed by, and experimental results are interpreted with, the help of two-dimensional (2-D), time-dependent magnetohydrodynamic (MHD) numerical simulations. When not driven by a second discharge, the toroids relax to a Woltjer--Taylor equilibrium state that compares favorably to the results of 2-D equilibrium calculations and to 2-D time-dependent MHD simulations. Current, voltage, and magnetic probe data from toroids that are driven by an acceleration discharge are compared to 2-D MHD and to circuit solver/slug model predictions. Results suggest that compact toroids are formed in 7--15 [mu]sec, and can be accelerated intact with material species the same as injected gas species and entrained mass [ge]1/2 the injected mass.

OSTI ID:
7369133
Journal Information:
Physics of Fluids B; (United States), Vol. 5:8; ISSN 0899-8221
Country of Publication:
United States
Language:
English