Application of an impedance matching transformer to a plasma focus

Bures, Brian; James, C.; Krishnan, M.; Adler, R. J.

doi:10.1063/1.3648117

Cited by 12 publications

(5 citation statements)

References 10 publications

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“…Finally, we note that the uniqueness of this instrument setup found in the diagnostic suite used may be used to investigate other classes of DPF. Most promising among these is a device based on a current transformer [22], which gives yet higher neutron yield at a given voltage used, due to enhancement of the current. This provides a stronger acceleration of the plasma sheath during run-in; a fundamental understanding of numerous physical aspects of this scenario would benefit from more precise diagnostic systems.…”

Section: Discussionmentioning

confidence: 99%

“…The advantages of such small devices, in the 100 J range or below, found in their low cost, compactness, and flexible operating modes, are attractive, as is the short pulse length described above. These advantages are counterbalanced by the relatively low neutron yield per pulse, and techniques have been explored, such as the use of current transformers [22] and piston gases [23][24][25][26][27][28], to mitigate the yield issue. The device we describe in this paper permits explorations of the physics of these smaller-scale DPFs.…”

Section: Introductionmentioning

confidence: 99%

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Simultaneous Ultra-Fast Imaging and Neutron Emission from a Compact Dense Plasma Focus Fusion Device

et al. 2018

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Recently, there has been intense interest in small dense plasma focus (DPF) devices for use as pulsed neutron and X-ray sources. Although DPFs have been studied for decades and scaling laws for neutron yield versus system discharge current and energy have been established (Milanese, M. et al., Eur. Phys. J. D 2003, 27, 77-81), there are notable deviations at low energies due to contributions from both thermonuclear and beam-target interactions (Schmidt, A. et al., Phys. Rev. Lett. 2012, 109, 1-4). For low energy DPFs (100 s of Joules), other empirical scaling laws have been found (Bures, B.L. et al., Phys. Plasmas 2012, 112702, 1-9). Although theoretical mechanisms to explain this change have been proposed, the cause of this reduced efficiency is not well understood. A new apparatus with advanced diagnostic capabilities allows us to probe this regime, including variants in which a piston gas is employed. Several complementary diagnostics of the pinch dynamics and resulting X-ray neutron production are employed to understand the underlying mechanisms involved. This apparatus is unique in its employment of a 50 fs laser-based shadowgraphy system that possesses unprecedented spatio-temporal resolution.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Simultaneous Ultra-Fast Imaging and Neutron Emission from a Compact Dense Plasma Focus Fusion Device

et al. 2018

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“…In this paper, numerical experiments for the following nine devices were carried to study the total D-D fusion neutron yield versus pressure: PF50 [20], AACS [21], PF400J [22], PF2.2 [23], UNU-ICTP [24], PFZ200 [25], PF24 [18], PF78 [26] and Poseidon [27]. The study of discharge current, pinch current and pinch ion density as functions of pressure are presented and their effect on the neutron yield is discussed as well.…”

Section: Introductionmentioning

confidence: 99%

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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“…33 The electrode geometry for this DPF consists of a central anode column of radius 0.75 cm, height 2.0 cm, surrounded by 12 cathode posts at a radius of 2.5 cm. Simulations of this set-up are carried out for currents of 70 kA and 500 kA with initial deuterium densities of 2 Â10 À4 kg m À3 and 1:53 Â 10 À2 kg m À3 , respectively.…”

Section: B 2 Ma Dpfmentioning

confidence: 99%

Neutron spectra from beam-target reactions in dense Z-pinches

Appelbe

Chittenden

2015

Physics of Plasmas

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The energy spectrum of neutrons emitted by a range of deuterium and deuterium-tritium Z-pinch devices is investigated computationally using a hybrid kinetic-MHD model. 3D MHD simulations are used to model the implosion, stagnation, and break-up of dense plasma focus devices at currents of 70 kA, 500 kA, and 2 MA and also a 15 MA gas puff. Instabilities in the MHD simulations generate large electric and magnetic fields, which accelerate ions during the stagnation and break-up phases. A kinetic model is used to calculate the trajectories of these ions and the neutron spectra produced due to the interaction of these ions with the background plasma. It is found that these beam-target neutron spectra are sensitive to the electric and magnetic fields at stagnation resulting in significant differences in the spectra emitted by each device. Most notably, magnetization of the accelerated ions causes the beam-target spectra to be isotropic for the gas puff simulations. It is also shown that beam-target spectra can have a peak intensity located at a lower energy than the peak intensity of a thermonuclear spectrum. A number of other differences in the shapes of beam-target and thermonuclear spectra are also observed for each device. Finally, significant differences between the shapes of beam-target DD and DT neutron spectra, due to differences in the reaction cross-sections, are illustrated.

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Application of an impedance matching transformer to a plasma focus

Cited by 12 publications

References 10 publications

Simultaneous Ultra-Fast Imaging and Neutron Emission from a Compact Dense Plasma Focus Fusion Device

Simultaneous Ultra-Fast Imaging and Neutron Emission from a Compact Dense Plasma Focus Fusion Device

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

Neutron spectra from beam-target reactions in dense Z-pinches

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