Temporal Variation of the Current Sheet Inductance from PACO Plasma Focus Device

Barbaglia, Mario Oscar; Milanese, M.; Soto, Leopoldo; Clausse, Alejandro; Moreno, José; Pavez, Cristian; Moreno, C.

doi:10.1007/s10894-016-0061-6

Cited by 4 publications

(4 citation statements)

References 33 publications

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“…The monotonic increase in calculated inductance particularly after the current derivative minimum in Figure 81 has not been interpreted. It is interesting to note that this feature has been observed in other studies as well, including on PF-3 [387], PACO [388] and a 400 J PF in Chile [216]. The conjecture that the inductance should vary as logarithm of the pinch radius [1,2,387] should imply that the inductance should reach a maximum at the minimum radius and then decrease.…”

supporting

confidence: 62%

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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supporting

confidence: 62%

Update on the Scientific Status of the Plasma Focus

Auluck

Kubeš

Paduch

et al. 2021

Plasma

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“…Interpretation of this diagnostic data [1,2,9,10] involves representing the plasma discharge as a circuit element, usually as a time varying inductance, in a circuit schematic that can be found in the cited references and is therefore not duplicated here. Evaluation of this "interpreted inductance" for PF-1000 [11,12] shows a quantity monotonically increasing with time, an observation also confirmed on smaller devices [13,14]. Sometimes, the voltage spike, that is time-correlated but not simultaneous [15] with the sharp current derivative minimum, is interpreted as being the result of an anomalous impedance [2] ascribed to micro-instabilities.…”

mentioning

confidence: 75%

“…The monotonic increase of "interpreted inductance" [11,12,13,14] after the pinch breakup and the delay between the pinch breakup and current derivative minimum in a neon plasma focus [18] both become understandable in terms of the above discussion. Notice that the plasma inductance (10) is not limited to the magnetic field generated by the current that flows in the external circuit but involves all three components of the magnetic field.…”

mentioning

confidence: 87%

On the representation of dense plasma focus as a circuit element

Auluck

2021

Physics of Plasmas

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Space propulsion is unique among many proposed applications of the Dense Plasma Focus in being critically dependent on the availability of a scaling theory that is well-grounded in physics, in conformity with existing experimental knowledge and applicable to experimentally untested configurations. This paper derives such a first-principles-based scaling theory and illustrates its application to a novel space propulsion concept, where the plasma focus sheath is employed as a power density amplifying mechanism to transport electric energy from a capacitive storage to a current-driven fusion load. For this purpose, a Generalized Plasma Focus problem is introduced and formulated. It concerns a finite, axisymmetric plasma, driven through a neutral gas at supersonic speed over distances much larger than its typical gradient scale length by its azimuthal magnetic field while remaining connected with its pulse power source through suitable boundaries. The Gratton-Vargas equation is rederived from the scaling properties of the equations governing plasma dynamics and solved for algebraically defined initial (insulator) and boundary (anode) surfaces. Scaling relations for a new space propulsion concept are derived. This consists of a modified plasma focus with a tapered anode that transports current from a pulsed power source to a consumable portion of the anode in the form of a hypodermic needle tube continuously extruded along the axis of the device. When the tube is filled with deuterium, the device may serve as a small-scale version of magnetized liner inertial fusion (MAGLIF) that could avoid failure of neutron yield scaling in a conventional plasma focus.

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“…Analysis of two or three cycles of the current waveform yields approximate values of L e and R e , provided that the bank capacitance (C 0 ) is known [6,8]. The electrical parameters of the PF, such as the plasma inductance and plasma resistance, are time-varying parameters that are affected by the variation in the charging voltage and the working gas pressure [11][12][13][14][15][16]. Experimental investigations show that the focus action in a PF device is affected by a number of factors, including the inner electrode (IE) length and material [17][18], the insulator sleeve length and material [19][20], the polarity of the IE [9] and the pressure of the filling gas [22][23].…”

Section: Introductionmentioning

confidence: 99%

Plasma Current Sheath Dynamics and Energy Dissipation in a Low-Energy Plasma Focus Device

Lashin

Allam

Ahmed

et al. 2019

Arab Journal of Nuclear Sciences and Applications

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The present study reports the measurements of plasma current sheath (PCS) dynamics, the energy dissipation processes, and the plasma focus (PF) electrical characteristics, particularly during the axial phase discharge in a Mather-type PF device (EAEA-PF1) energized with a 30 µF capacitor bank charged with 8, 10 and 12 kV. All these investigations carried out under discharge conditions where the optimal PF action is achieved. At each charging voltage (V ch), 8 kV, 10 kV and 12 kV, the optimal PF action is studied at different argon gas pressures (P) ranging from 0.4 to 1.2 Torr. The results show that the best PF is formed at V ch = 8 kV and P = 0.6 Torr, V ch = 10 kV and P = 0.8 Torr, and V ch = 12 kV and P = 0.8 Torr. The implosion velocity (V z) results of PCS show that the maximum value of V z (4.48 cm/µs) occurs at the end of the axial phase (i.e., at the coaxial electrode muzzle), which is detected at V ch = 12 kV and P = 0.8 Torr. Moreover, a less inefficient snowplow action is observed under these discharge conditions. The energy dissipation process data indicate that at V ch = 12 kV and P = 0.8 Torr, the ratio between the total energy dissipation and the input energy has a maximum value of 90%, and the minimum residual energy left on the condenser bank (175.39 J) is also achieved under these discharge conditions.

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Temporal Variation of the Current Sheet Inductance from PACO Plasma Focus Device

Cited by 4 publications

References 33 publications

Update on the Scientific Status of the Plasma Focus

Update on the Scientific Status of the Plasma Focus

On the representation of dense plasma focus as a circuit element

Plasma Current Sheath Dynamics and Energy Dissipation in a Low-Energy Plasma Focus Device

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