Design Parameter Space for a High Pressure Optimized Dense Plasma Focus Operating with Deuterium

Auluck, S. K. H.

doi:10.1007/s10894-017-0142-1

Cited by 3 publications

(6 citation statements)

References 25 publications

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“…This is discussed in a separate section on empirical and analytical insights. The analytical treatment of energy transfer in the RGV model has been used to construct device optimization algorithms [317,318].…”

Section: (C))mentioning

confidence: 99%

“…What are the underlying physical mechanisms that place upper or lower bounds on the density and magnetic field? Is it because nobody has explored a plasma focus design that might operate at a much higher density [318] or magnetic field or because of a real phenomenon nobody has thought of before?…”

Section: Contours Of the "Emerging Narrative"mentioning

confidence: 99%

“…It would seem that an objective definition of "optimization" [318] should involve the fraction of energy remaining in the capacitor bank at the time of the pinch. The lower this fraction, the better optimized the device would be.…”

Section: "Optimization" Of Pf Devicesmentioning

confidence: 99%

“…These are expected to break new ground and enable discovery of plasma focus physics in new regions of parameter space. One possibility is the optimized operation of plasma focus at deuterium pressures of 0.1 to 1 bar [318].…”

Section: Longer Term Activities (2-10 Years)mentioning

confidence: 99%

“…It can, however, be used to provide a mathematical framework for constructing a first-principles theory of plasma focus sheath propagation based on conservation of mass, momentum, and energy, and perhaps other physical principles [171,316]. It can also be used for construction of algorithms that optimize energy transfer efficiency as a function of device parameters [317,318].…”

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confidence: 99%

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Update on the Scientific Status of the Plasma Focus

Auluck

Kubeš

Paduch

et al. 2021

Plasma

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This paper is a sequel to the 1998 review paper “Scientific status of the Dense Plasma Focus” with 16 authors belonging to 16 nations, whose initiative led to the establishment of the International Center for Dense Magnetized Plasmas (ICDMP) in the year 2000. Its focus is on understanding the principal defining characteristic features of the plasma focus in the light of the developments that have taken place in the last 20 years, in terms of new facilities, diagnostics, models, and insights. Although it is too soon to proclaim with certainty what the plasma focus phenomenon is, the results available to date conclusively indicate what it is demonstrably not. The review looks at the experimental data, cross-correlated across multiple diagnostics and multiple devices, to delineate the contours of an emerging narrative that is fascinatingly different from the standard narrative, which has guided the consensus in the plasma focus community for several decades, without invalidating it. It raises a question mark over the Fundamental Premise of Controlled Fusion Research, namely, that any fusion reaction having the character of a beam-target process must necessarily be more inefficient than a thermonuclear process with a confined thermal plasma at a suitably high temperature. Open questions that need attention of researchers are highlighted. A future course of action is suggested that individual plasma focus laboratories could adopt in order to positively influence the future growth of research in this field, to the general benefit of not only the controlled fusion research community but also the world at large.

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Section: (C))mentioning

confidence: 99%

Section: Contours Of the "Emerging Narrative"mentioning

confidence: 99%

Section: "Optimization" Of Pf Devicesmentioning

confidence: 99%

Section: Longer Term Activities (2-10 Years)mentioning

confidence: 99%

mentioning

confidence: 99%

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Update on the Scientific Status of the Plasma Focus

Auluck

Kubeš

Paduch

et al. 2021

Plasma

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Axial magnetic field and toroidally streaming fast ions in the dense plasma focus are natural consequences of conservation laws in the curved axisymmetric geometry of the current sheath. II. Towards a first principles theory

Auluck¹

2017

Physics of Plasmas

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This paper continues earlier discussion [S. K. H. Auluck, Phys. Plasmas 21, 102515 (2014)] concerning the formulation of conservation laws of mass, momentum, and energy in a local curvilinear coordinate system in the dense plasma focus. This formulation makes use of the revised Gratton-Vargas snowplow model [S. K. H. Auluck, Phys. Plasmas 20, 112501 (2013)], which provides an analytically defined imaginary surface in three dimensions which resembles the experimentally determined shape of the plasma. Unit vectors along the local tangent to this surface, along the azimuth, and along the local normal define a right-handed orthogonal local curvilinear coordinate system. The simplifying assumption that physical quantities have significant variation only along the normal enables writing laws of conservation of mass, momentum, and energy in the form of effectively one-dimensional hyperbolic conservation law equations using expressions for various differential operators derived for this coordinate system. This formulation demonstrates the highly non-trivial result that the axial magnetic field and toroidally streaming fast ions, experimentally observed by multiple prestigious laboratories, are natural consequences of conservation of mass, momentum, and energy in the curved geometry of the dense plasma focus current sheath. The present paper continues the discussion in the context of a 3-region shock structure similar to the one experimentally observed: an unperturbed region followed by a hydrodynamic shock containing some current followed by a magnetic piston. Rankine-Hugoniot conditions are derived, and expressions are obtained for the specific volumes and pressures using the mass-flux between the hydrodynamic shock and the magnetic piston and current fraction in the hydrodynamic shock as unknown parameters. For the special case of a magnetic piston that remains continuously in contact with the fluid being pushed, the theory gives closed form algebraic results for the fraction of current flowing in the hydrodynamic shock, specific volume, pressure, and fluid velocity of the hydrodynamic shock region, the tangential, normal, and azimuthal components of velocity in the magnetized plasma, the density of the magnetized plasma, the normal and tangential components of the magnetic field, and the tangential, normal, and azimuthal components of the electric field. This explains the occurrence of azimuthally streaming high energy deuterons experimentally observed by Frascati and Stuttgart. The expression derived for the azimuthal component of vector potential can serve as the basis for a proposed experimental test of the theory.

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A study of the effects of the cathode configuration on the plasma kinetics and neutron emission of plasma-focus discharges in deuterium

Barbaglia

Giovachini

Milanese

et al. 2020

Plasma Phys. Control. Fusion

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The differences in performance of a 1.9 kJ plasma-focus device PACO assembled with three different cathode configurations are experimentally qualified. In particular, the current sheath kinetics and the neutron yield operating with deuterium gas are systematically studied for the whole range of neutron-producing pressures, and the measurements are analyzed searching for relations between relevant physical magnitudes. The pinching time was found correlated with the dimensionless driver parameter, and this feature was found statistically independent of the cathode. The variation of the inductance jump associated with the radial collapse stage is used to estimate the effective pinch length, ( )  7.3 1.6 mm, and radius, ( )  3.6 2.1 mm. The maximum production in a single shot was registered for the smallest cathode radius, 41 mm, whereas the intermediate cathode radius, 45 mm, scored better in average. In all configurations, the neutrons per deuteron pair correlates fairly well with an estimation of the effective equilibrium temperature of the pinch, which suggests a prevalence of thermonuclear neutrons measured perpendicularly to the focus axis.

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Design Parameter Space for a High Pressure Optimized Dense Plasma Focus Operating with Deuterium

Cited by 3 publications

References 25 publications

Update on the Scientific Status of the Plasma Focus

Update on the Scientific Status of the Plasma Focus

Axial magnetic field and toroidally streaming fast ions in the dense plasma focus are natural consequences of conservation laws in the curved axisymmetric geometry of the current sheath. II. Towards a first principles theory

A study of the effects of the cathode configuration on the plasma kinetics and neutron emission of plasma-focus discharges in deuterium

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