Axial Velocity Measurement of Current Sheath in a Plasma Focus Device Using a Magnetic Probe

Al‐Hawat, Sh.

doi:10.1109/tps.2004.826119

Cited by 27 publications

(9 citation statements)

References 9 publications

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“…The dense plasma focus [1] (DPF) is a laboratory plasma fusion device with a rich and complex phenomenology [2,3]; yet it also has strikingly simple universal properties which hold over 8 decades in capacitor bank storage energy: neutron yield Y scales as the fourth power of pinch current I p [3,4], the ratio of capacitor bank energy to the cube of anode radius is nearly constant [4] and the drive parameter 0 I p a , with p 0 the fill gas pressure, I the maximum current and a the anode radius, is nearly constant [4,5]. One of the conclusions of DPF research over the last 50 years is that the plasma current sheath (PCS) propagation is quite well described by the snowplow model [6,7,8], which assumes that the sheath acquires a velocity and shape dictated by a balance between magnetic pressure 2 0 2 B μ driving the plasma into the neutral gas and "wind pressure" 2 0 v ρ resisting it:…”

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confidence: 99%

Bounds imposed on the sheath velocity of a dense plasma focus by conservation laws and ionization stability condition

Auluck

2014

Physics of Plasmas

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Abstract:Experimental data compiled over five decades of dense plasma focus research is consistent with the snowplow model of sheath propagation, based on the hypothetical balance between magnetic pressure driving the plasma into neutral gas ahead and "wind pressure" resisting its motion. The resulting sheath velocity, or the numerically proportional "drive parameter", is known to be approximately constant for devices optimized for neutron production over 8 decades of capacitor bank energy. This paper shows that the validity of the snowplow hypothesis, with some correction, as well as the non-dependence of sheath velocity on device parameters, have their roots in local conservation laws for mass, momentum and energy coupled with the ionization stability condition. Both upper and lower bounds on sheath velocity are shown to be related to material constants of the working gas and independent of the device geometry and capacitor bank impedance.Key words: Dense plasma focus, drive parameter, conservation laws, snowplow model, RankineHugoniot conditions, ionizing shock waves, ionization stability condition.The dense plasma focus[1] (DPF) is a laboratory plasma fusion device with a rich and complex phenomenology [2,3]; yet it also has strikingly simple universal properties which hold over 8 decades in capacitor bank storage energy: neutron yield Y scales as the fourth power of pinch current I p [3,4], the ratio of capacitor bank energy to the cube of anode radius is nearly constant [4] and the drive parameter 0 I p a , with p 0 the fill gas pressure, I the maximum current and a the anode radius, is nearly constant [4,5]. One of the conclusions of DPF research over the last 50 years is that the plasma current sheath (PCS) propagation is quite well described by the snowplow model [6,7,8], which assumes that the sheath acquires a velocity and shape

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confidence: 99%

Bounds imposed on the sheath velocity of a dense plasma focus by conservation laws and ionization stability condition

Auluck

2014

Physics of Plasmas

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“…Wherer p is the average value of r p , B is the magnetic field which was measured experimentally [20]. Using the obtained factors and the transit time of the axial phase measured from the experiment, the computation of plasma dynamics was carried out.…”

Section: Wwwcpp-journalorg 4 Resultsmentioning

confidence: 99%

Characterization of a 2.8 kJ Small Plasma Focus Using a Five Phase Radiative Model

Al‐Hawat

Saloum

2009

Contrib. Plasma Phys.

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A radiative five-phase plasma focus model (axial phase, inward radial phase, reflected shock phase, radiative phase and expanded phase) was applied to a 2.8 kJ plasma focus device to find the structure of the plasma focus formation and to calculate the plasma parameters and emitted radiation from the plasma pinch. To verify the model, the radiation probability of such device in neon plasma has been studied; a linear approximation method was applied by a FORTRAN program which has been written for this purpose. The theoretical and experimental results of the temporal development of current and voltage at 0.9 mbar of neon and spike voltages at different filling gas pressures were obtained and compared. In addition to that our plasma focus (PF) device was compared with different PF devices in relation to the plasma energy density and the drive parameter.

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“…This approximation is nearly true at high pressure [8], [9]. The change of momentum equation due to the force from (JxB).…”

Section: Theoretical Modelmentioning

confidence: 96%

Current Sheet Axial Dynamics of 2.5-kJ KSU-DPF Under High-Pressure Regime

Mohamed

Abdou

Ismail

et al. 2012

IEEE Trans. Plasma Sci.

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Axial Velocity Measurement of Current Sheath in a Plasma Focus Device Using a Magnetic Probe

Cited by 27 publications

References 9 publications

Bounds imposed on the sheath velocity of a dense plasma focus by conservation laws and ionization stability condition

Bounds imposed on the sheath velocity of a dense plasma focus by conservation laws and ionization stability condition

Characterization of a 2.8 kJ Small Plasma Focus Using a Five Phase Radiative Model

Current Sheet Axial Dynamics of 2.5-kJ KSU-DPF Under High-Pressure Regime

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