Ablation dynamics in coiled wire-array Z-pinches
File(s)
Published version
Author(s)
Type
Journal Article
Abstract
Experiments to study the ablation dynamics of coiled wire arrays were performed on the MAGPIE
generator (1 MA, 240 ns) at Imperial College, and on the COBRA generator at Cornell University’s
Laboratory of Plasma Studies (1 MA, 100 ns). The MAGPIE generator was used to drive coiled wires
in an inverse array configuration to study the distribution of ablated plasma. Using interferometry to
study the plasma distribution during the ablation phase, absolute quantitative measurements of
electron line density demonstrated very high density contrasts between coiled ablation streams and
inter-stream regions many millimetres from the wire. The measured density contrasts for a coiled
array were many times greater than that observed for a conventional array with straight wires,
indicating that a much greater axial modulation of the ablated plasma may be responsible for the
unique implosion dynamics of coiled arrays. Experiments on the COBRA generator were used to
study the complex redirection of plasma around a coiled wire that gives rise to the ablation structure
exhibited by coiled arrays. Observations of this complex 3D plasma structure were used to validate
the current model of coiled array ablation dynamics [Hall et al., Phys. Rev. Lett. 100, 065003
(2008)], demonstrating irrefutably that plasma flow from the wires behaves as predicted. Coiled wires
were observed to ablate and implode in the same manner on both machines, indicating that current
rise time should not be an issue for the scaling of coiled arrays to larger machines with fast current
rise times.
generator (1 MA, 240 ns) at Imperial College, and on the COBRA generator at Cornell University’s
Laboratory of Plasma Studies (1 MA, 100 ns). The MAGPIE generator was used to drive coiled wires
in an inverse array configuration to study the distribution of ablated plasma. Using interferometry to
study the plasma distribution during the ablation phase, absolute quantitative measurements of
electron line density demonstrated very high density contrasts between coiled ablation streams and
inter-stream regions many millimetres from the wire. The measured density contrasts for a coiled
array were many times greater than that observed for a conventional array with straight wires,
indicating that a much greater axial modulation of the ablated plasma may be responsible for the
unique implosion dynamics of coiled arrays. Experiments on the COBRA generator were used to
study the complex redirection of plasma around a coiled wire that gives rise to the ablation structure
exhibited by coiled arrays. Observations of this complex 3D plasma structure were used to validate
the current model of coiled array ablation dynamics [Hall et al., Phys. Rev. Lett. 100, 065003
(2008)], demonstrating irrefutably that plasma flow from the wires behaves as predicted. Coiled wires
were observed to ablate and implode in the same manner on both machines, indicating that current
rise time should not be an issue for the scaling of coiled arrays to larger machines with fast current
rise times.
Date Issued
2013-02-06
Date Acceptance
2013-01-10
Citation
Physics of Plasmas, 2013, 20 (2)
ISSN
1089-7674
Publisher
American Institute of Physics (AIP)
Journal / Book Title
Physics of Plasmas
Volume
20
Issue
2
Copyright Statement
© 2013 American Institute of Physics
Subjects
Science & Technology
Physical Sciences
Physics, Fluids & Plasmas
Physics
PHYSICS, FLUIDS & PLASMAS
IMPLOSION PHASE
X-PINCH
Publication Status
Published
Article Number
ARTN 022703