An ultra-fast pinch experiment

Adlam, J.H.; Holmes, L. S.

doi:10.1088/0029-5515/3/2/002

Cited by 17 publications

(7 citation statements)

References 8 publications

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“…In ultra-fast pinch experiments [18] Adlam et al observed broadening of the skin layer compared with the value given by expression (5.11) by a factor of 25 (n 0 ~2X10 1 5 cm" 3 , 6 exp = 0. 3 -0.…”

Section: Penetration Of a Low-frequency Electromagnetic Field Into A ...mentioning

confidence: 84%

Anomalous resistance of plasmas in sub-critical electric fields

Sizonenko

Степанов

1970

Nucl. Fusion

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On the basis of the theory of weak turbulence it is shown that the principal mechanism limiting the development of ion-acoustic instability in a current-carrying plasma in an electric field can be the non-linear scattering of oscillations by electrons. The energy density of turbulent ion-acoustic pulsations is of the order W∼(2me/mi)n0 Te, where n0 is the plasma density, Te the electron temperature and m6ij the electron and ion mass.Electron scattering by turbulent pulsations occurs with an effective frequency νs ∼ (2me/mi) ωpe and leads to an anomalous effective plasma conductivity , where ωpe is the electron Langmuir frequency.Ion-acoustic instability develops in a plasma in weak electric fields (E

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Section: Penetration Of a Low-frequency Electromagnetic Field Into A ...mentioning

confidence: 84%

Anomalous resistance of plasmas in sub-critical electric fields

Sizonenko

Степанов

1970

Nucl. Fusion

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“…To obtain a velocity of compression that will yield fusion temperatures, or to ohmically heat a Z-pinch column to fusion temperatures, an applied voltage of the order of 106 V and a current of 106 A is required. While early attempts were made by Heflinger & Leonard (1961) and by Adlam & Holmes (1963) based on a proposal of J. E. Allen & J. H. Adlam (private communication), it was not until the recent development of high voltage pulse technology and the speculation of large ion Larmor radius stabilization that a new approach to Z-pinches was possible.…”

Section: Z -Pinch (A) Generalmentioning

confidence: 99%

Dense plasma in Z-pinches and the plasma focus

Haines

1981

Phil. Trans. R. Soc. Lond. A

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Many of the earliest experiments in controlled thermonuclear fusion research were Z -pinches. However these pinches were found to be highly unstable to the m = 0, the m — 1 (kink), and the Rayleigh-Taylor instability. The addition of an axial magnetic field and the removal of end losses by proceeding to a toroidal geometry has led to the class of discharges known as tokamaks and the reversed field pinch. But, at fusion temperatures and with practical values of applied magnetic field this restricts the plasma density to 10 20 to 10 21 m- 3 , thereby requiring a containment time of several seconds and a plasma radius of about 1 m. Meanwhile studies of the plasma focus, which after its three-dimensional compression closely resembles a Z -pinch, have shown that a plasma of density 10 25 m- 3 and temperature 1 keV can be achieved in a narrow filament of radius 1 mm. It has enhanced stability properties which might be attributable to the effects of finite ion Larmor radius. Its neutron yield in deuterium can be as high as 10 12 per discharge, with a favourable empirical scaling law, but the thermonuclear origin of the neutrons is doubtful because of the evidence of centre-of-mass motion and the formation of electron and ion beams. The development of high voltage, high current pulse technology has permitted the reconsideration of the Z -pinch to attain dense fusion plasmas which might be stabilized by scaling the ion Larmor radius to be comparable with the pinch radius. Experiments at Imperial College show that the plasma remains stationary for about twenty Alfven radial transit times, limited only by the period of the current waveform. Theory indicates that a dense compact Z -pinch can satisfy Lawson conditions with a power input dependent on the enhanced stability time, or, if stable, with ohmic heating balancing axial heat losses. Preliminary results on a laser-initiated Z -pinch are also presented.

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“…The explicit form of the integrals depends on the ratio of the cyclotron frequency to the collision frequency: (6) A similar calculation makes it possible to represent the heat flux density in the form (7) Formulas ( 4)- (7) form the basis for further consideration of the effect of charge and energy transfer of electrons on the nonlinear penetration of a heating pulse into plasma. 10 )) . 2…”

Section: Current and Heat Flux Densitymentioning

confidence: 99%

“…Therefore the initial conditions for Eqs. (10), (11) have the form (12) The boundary conditions are derived from the continuity conditions for the tangential field components at the layer boundaries. Taking into account the smallness of the displacement current the boundary conditions have the form: (13) According to Eqs.…”

Section: / ) E N Mmentioning

confidence: 99%

“…Nonlinear penetration of monochromatic field into plasma with ion-acoustic turbulence was studied in [8,9]. Penetration of strong quasistationary electric field into nonisothermal plasma was studied in [6,10,11]. A number of works are devoted to consideration of penetration of relatively weak electric field into turbulent [12][13][14] or laminar [15] plasma with time-varying electron and ion temperatures.…”

Section: Introductionmentioning

confidence: 99%

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Penetration of a Heating Electromagnetic Pulse into Plasma in Magnetic Field

2022

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Penetration of a heating pulse of quasistationary electromagnetic field into plasma in constant magnetic field directed along its surface was studied. Weakening of electron heat transfer across the magnetic field leads to more efficient heating of electrons near the plasma surface. As a result, the penetration of the field into the plasma decreases, which is accompanied by suppression of the “inverse” skin effect. Inhomogeneous heating of electrons across the magnetic field leads to generation of an electric field strength component orthogonal to both the magnetic field and the direction of temperature gradient. Appearance of the additional field strength component leads to a change in polarization of the reflected pulse. In a sufficiently strong magnetic field, due to suppression of the electron heat flux and less significant effect of the magnetic field on the ion heat flux, a state with large difference of electron and ion temperatures occurs.

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An ultra-fast pinch experiment

Cited by 17 publications

References 8 publications

Anomalous resistance of plasmas in sub-critical electric fields

Anomalous resistance of plasmas in sub-critical electric fields

Dense plasma in Z-pinches and the plasma focus

Penetration of a Heating Electromagnetic Pulse into Plasma in Magnetic Field

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