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Standardized
aluminum liner for Pegasus. As the Marx capacitor bank discharges,
electrical current flows in the liner's outer skin creating a strong
magnetic field (B). The interaction of the current and magnetic
field produces forces that implode the liner. The experimental target
is often located inside the liner.
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The
Pegasus Pulsed-Power Facility,
which fired its last shot in 1999, provided a unique capability
for delivering strong, converging, shock-driven or adiabatically
driven compressions with excellent diagnostics. Pegasus
allowed physicists to gather important data on material
behavior at high-energy-densities, which are necessary
for weapons physics and basic science.
Hydrodynamic
Instabilities
Our studies
of the hydrodynamic flow of materials under extreme conditions
are crucial to developing and testing weapons models. Our
experiments focussed on instabilities at the interface between
two materials of different densities.
Material
Properties
Our studies
of the properties of materials under extreme conditions
included topics such as material failure through spall and
ejecta, plastic deformations, strain and strain-rate effects,
and interfacial friction. One significant series, carried
out in collaboration with Livermore, focussed on spallation
of shocked aluminum targets and the growth of instabilities
(see images at right).
Basic
Science and Technology
We explored
the electronic properties of materials in the presence of
strong magnetic fields, and we collaborated with Russian
scientists to study liner stability. In preparation for
the future Atlas facility, we also conducted experiments
on mechanical joints that can carry high current-densities.
Atlas:
The Next Generation of Pulsed Power
The Atlas
Pulsed-Power Facility is now under construction. This facility
will deliver 2 to 5 MJ of kinetic energy to nominal 8-cm-diameter,
50-g liners, making possible many new experiments in dynamic
materials properties and hydrodynamics.
For
more information, see the full
Pegasus research highlight (PDF 118 KB),
or
contact David Oro (doro@lanl.gov).
 RETURN to the Beams and Hydrodynamics Page
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Flash
radiographs of the LLNL-5 experiment before and 3.38 microseconds
after the liner has impacted the target. The 2.2 km/s impact resulted
in a 140-kbar shock. In the later image, the shock has left the
aluminum target and is traveling toward the xenon center. Visible
are the boundary between shocked and unshocked xenon, layers of
spalled aluminum, regions of "failed" aluminum, and jets
seeded by perturbations in the target's inner surface.
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