Effect of insulator length and fill pressure on filamentation and neutron production in a 4.6 kJ dense plasma focus

Hahn, Eric N.; Ghosh, Samir; Eudave, V.; Narkis, J.; Angus, J. R.; Link, A.; Conti, F.; Beg, F. N.

doi:10.1063/5.0087901

Cited by 4 publications

(2 citation statements)

References 48 publications

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“…These phenomena may be important for the described Y n vs p 0 dependency, as some authors have already suggested, e.g. Milanese et al [41], Kubes et al [42], Bennett et al [43] and Hahn et al [44]. On the other hand, the influence of filamentation on a PF discharge during axial and radial phases prior to the plasma pinch formation may already be approximately included through the Lee model code parameters.…”

Section: Discussionmentioning

confidence: 92%

Numerical experiments on the total D–D fusion neutron yield versus deuterium pressure for different energy plasma focus devices using the Lee model code

Wahbe¹,

Abou-Ali²,

Akel³

et al. 2023

Plasma Phys. Control. Fusion

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Numerical experiments using the Lee model code were carried out to compute the total D-D fusion neutron yield versus initial deuterium pressure for nine different plasma focus devices [PF50, AACS, PF400J, PF2.2, UNU-ICTP, PFZ200, PF24, PF78, Poseidon]. The computed data were compared with the published experimental results. In addition, the maximum discharge current, the pinch current and the pinch ion number density as a function of initial deuterium pressure were discussed as well as their effect on the neutron yield. The optimum pressures that correspond to the maximum neutron yield Yn were obtained for all considered devices, with reference to the specific plasma focus properties. The scaling laws for the D-D fusion neutron production, in terms of storage energies E0 and pinch current Ipinch were derived. The scaling of Yn with Ipinch and E0 over the whole range of investigated energies up to 300 kJ has been obtained as follows: (Y_n~I_pinch^5 ,Y_n~E_0^1.95 ). These laws are important for planning and designing a plasma focus as a potentially powerful pulse neutron source.

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Section: Discussionmentioning

confidence: 92%

Numerical experiments on the total D–D fusion neutron yield versus deuterium pressure for different energy plasma focus devices using the Lee model code

Wahbe¹,

Abou-Ali²,

Akel³

et al. 2023

Plasma Phys. Control. Fusion

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show abstract

“…The gas employed at the experiments were H 2 and D 2 , while the working pressure was specified in each situation. It is worth noting that the working pressures for the MPG correspond to those that are defined in the standard narrative as a high-pressure regime (>6 mbar), which is characterized by the formation of filamentary discharges and low performance as for the neutron emission and radiation [32,33].…”

Section: Multipurpose Generatormentioning

confidence: 99%

New evidence about the nature of plasma filaments in plasma accelerators of type plasma-focus

Pavez¹,

Zorondo²,

Pedreros³

et al. 2022

Plasma Phys. Control. Fusion

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In this work, new evidence and information about both the origin and evolution of filamentary structures observed in the current sheath of a small plasma focus discharge are reported. The experiments were carried out in a small generator of low energy (multipurpose generator MPG), at the plasma focus configuration, under different operation conditions. These include different anode and insulator geometries, without return bars and a high-performance regime of the generator at high pressures (> 10 mbar). The evolution of the plasma structures is characterized by mean of refractive optical techniques. The electrical behavior of the discharge, as well as its performance, are monitored with conventional electrical diagnostics and neutron and X-ray detectors, respectively. Plasma filaments of the same species are present in all tested configurations, however, in those with a large effective anode length (and smaller anode radius), the plasma region containing the filaments moves away from the anode surface and it is confined in a region of the plasma sheath, such as a toroidal plasma belt, without reaching the anode top nor participating in the radial compression phase. According to images of the plasma sheath in its early phase, the filaments originate and evolve from a precursor annular plasma formed in the lower part of the anode next to the insulator, in the process of electrical breakdown. The local character that these dense-filamentary structures acquire in the evolution of the plasma sheath would discard the current-filament hypothesis. On the other hand, in experiments in deuterium gas with a large effective anode length and without filaments in the radial compression phase, a high performance at the neutron and X-rays production were obtained.

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The presence of high-energy neutrons in neutron pulses emitted from a kilojoule plasma focus device: Deuterium as a working gas

Jain,

Moreno,

Loyola

et al. 2023

Physics of Plasmas

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In the present work, a kilo-joule plasma focus device, PF-2kJ, is used as a pulsed neutron generator. Time of flight and neutron spectroscopic measurements suggest neutron energies larger than 5 MeV in the radial and axial directions. The anisotropy in neutron emission suggested a beam-target nuclear fusion mechanism. A simulation tool kit Geant4 is used to interpret and verify the experimentally observed spectroscopic results of neutrons' energies. Based on the findings, it is hypothesized that the pinch and pre-pinch phases invoke suitable conditions for the D–D reaction that produces proton and tritium. The produced tritium nuclei further collide with deuterons in the pinch and post-pinch phases and produce high-energy neutrons. However, the observed high-energy neutrons could be of mixed origin of beam-target nuclear fusion mechanism and D–T fusion reactions.

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Effect of insulator length and fill pressure on filamentation and neutron production in a 4.6 kJ dense plasma focus

Cited by 4 publications

References 48 publications

Numerical experiments on the total D–D fusion neutron yield versus deuterium pressure for different energy plasma focus devices using the Lee model code

Numerical experiments on the total D–D fusion neutron yield versus deuterium pressure for different energy plasma focus devices using the Lee model code

New evidence about the nature of plasma filaments in plasma accelerators of type plasma-focus

The presence of high-energy neutrons in neutron pulses emitted from a kilojoule plasma focus device: Deuterium as a working gas

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