The Role of the Self Magnetic Field in High Current Gas Discharges

Thonemann, P. C.; Cowhig, W. T.

doi:10.1088/0370-1301/64/4/308

Cited by 36 publications

(17 citation statements)

References 6 publications

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“…In the late 1940s experiments on Z-pinches were devised by Thomson and Blackman in 1946 at Imperial College resulting in a patent, figure 2, on a toroidal fusion reactor [27]. Theory by Blackman [28] and an experiment by Cousins and Ware [29] of the Z-pinch were published later. Parallel experimental work was undertaken also by Reynolds and Craggs [30] and also by Allen and Craggs [31] at the University of Liverpool.…”

Section: Historymentioning

confidence: 99%

“…Most of the earliest Z-pinch experiments were compressional Z-pinches in which there is initially a uniform fill of gas inside an insulating cylinder, at the ends of which are the two electrodes. In section 1.2 and [29][30][31][32][33][34][35][36] we reported some of these early experiments. They are characterized by the formation through the skin effect of a current sheet adjacent to the insulating wall, followed by an implosion.…”

Section: Compressional Z-pinchmentioning

confidence: 99%

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A review of the denseZ-pinch

Haines

2011

Plasma Phys. Control. Fusion

394

184

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The Z-pinch, perhaps the oldest subject in plasma physics, has achieved a remarkable renaissance in recent years, following a few decades of neglect due to its basically unstable MHD character. Using wire arrays, a significant transition at high wire number led to a great improvement in both compression and uniformity of the Z-pinch. Resulting from this the Z-accelerator at Sandia at 20 MA in 100 ns has produced a powerful, short pulse, soft x-ray source >230 TW for 4.5 ns) at a high efficiency of ∼15%. This has applications to inertial confinement fusion. Several hohlraum designs have been tested. The vacuum hohlraum has demonstrated the control of symmetry of irradiation on a capsule, while the dynamic hohlraum at a higher radiation temperature of 230 eV has compressed a capsule from 2 mm to 0.8 mm diameter with a neutron yield >3 × 10 11 thermal DD neutrons, a record for any capsule implosion. World record ion temperatures of >200 keV have recently been measured in a stainless-steel plasma designed for Kα emission at stagnation, due, it was predicted, to ion-viscous heating associated with the dissipation of fast-growing short wavelength nonlinear MHD instabilities. Direct fusion experiments using deuterium gas-puffs have yielded 3.9×10 13 neutrons with only 5% asymmetry, suggesting for the first time a mainly thermal source. The physics of wire-array implosions is a dominant theme. It is concerned with the transformation of wires to liquid-vapour expanding cores; then the generation of a surrounding plasma corona which carries most of the current, with inward flowing low magnetic Reynolds number jets correlated with axial instabilities on each wire; later an almost constant velocity, snowplough-like implosion occurs during which gaps appear in the cores, leading to stagnation on the axis, and the production of the main soft-x-ray pulse. These studies have been pursued also with smaller facilities in other laboratories around the world. At Imperial College, conical and radial wire arrays have led to highly collimated tungsten plasma jets with a Mach number of >20, allowing laboratory astrophysics experiments to be undertaken. These highlights will be underpinned in this review with the basic physics of Z-pinches including stability, kinetic effects, and finally its applications.

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Section: Historymentioning

confidence: 99%

Section: Compressional Z-pinchmentioning

confidence: 99%

A review of the denseZ-pinch

Haines

2011

Plasma Phys. Control. Fusion

394

184

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“…The ion temperature has been neglected and in equation (18) we have put F eθ = mv eθ ν e . We can note immediately that eqn.s (15), (16) and (17) all have a singularity when the radial component of the ion velocity reaches the ion acoustic velocity c s = (kT e /M ) 1 2 , which is the same as the Bohm velocity. For the purposes of the present (short) paper we shall be interested in eqn.s (16) and (17) which can be written as…”

Section: A Summary Of the Two Scale Modelmentioning

confidence: 95%

“…The case considered was that of the pinch effect, and included experimental work with a low pressure mercury arc, following pioneering work on the pinch effect by Thonemann and Cowhig [15]. The conclusion reached at that time was that the Bohm criterion was modified by a factor involving the electric field at the plasma boundary.…”

Section: The Plasma-sheath Transition In a Magnetic Field (Revisited)mentioning

confidence: 99%

The Plasma Boundary in a Magnetic Field

Allen

2008

Contrib. Plasma Phys.

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“…The case considered was that of the pinch effect, and included experimental work with a low pressure mercury arc, following the pioneering work on the pinch effect by Thonemann and Cowhig. 13 The conclusion reached at that time was that the Bohm condition involved a factor ͑1+vB / E s ͒, where v is the electron drift velocity and E s is the radial electric field at the plasma-sheath boundary, following the terminology of Tonks and Langmuir.…”

mentioning

confidence: 99%

Comment on “Magnetic field effects on gas discharge plasmas” [Phys. Plasmas 13, 063511 (2006)]

Allen¹

2007

Physics of Plasmas

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N. Sternberg, V. Godyak, and D. Hoffman [Phys. Plasmas 13, 063511 (2006)] have produced a detailed paper on a cylindrical plasma column in an axial magnetic field. The authors found that the radial component of the ion velocity, on leaving the plasma region, is the ion acoustic velocity. This is, of course, the Bohm velocity, but the authors did not comment on this fact. The Bohm criterion does appear to be of general validity, however, and perhaps a greater emphasis should have been given to this result.

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The Role of the Self Magnetic Field in High Current Gas Discharges

Cited by 36 publications

References 6 publications

A review of the denseZ-pinch

A review of the denseZ-pinch

The Plasma Boundary in a Magnetic Field

Comment on “Magnetic field effects on gas discharge plasmas” [Phys. Plasmas 13, 063511 (2006)]

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