Study of the effects of the prefilled-plasma parameters on the operation of a short-conduction plasma opening switch

Weingarten, A.; Bernshtam, V.; Fruchtman, A.; Grabowski, C.; Krasik, Ya. E.; Maron, Y.

doi:10.1109/27.808932

Cited by 15 publications

(13 citation statements)

References 27 publications

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“…The current density was found to be between 100 and 150 A / cm 2 , which corresponds to an ion density of ͑1 -1.5͒ ϫ 10 13 cm −3 , significantly lower than the proton density obtained spectroscopically. Faraday-cup saturation or incomplete insulation of the electron current, as has recently been observed 42 in experiments in which Faraday-cup signals were compared with spectroscopic data, is believed to be the reason for the low density inferred using this method.…”

Section: Proton Velocity Measurementsmentioning

confidence: 84%

Investigation of the ion dynamics in a multispecies plasma under pulsed magnetic fields

et al. 2004

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The interaction between a moving magnetic-field front and a low-collisionality plasma consisting of different ion species is investigated using spatially and temporally resolved spectroscopic techniques. The experiment is carried out in a plasma-opening-switch configuration, in which a current rising to 150 kA in 400 ns is conducted through a plasma that prefills the region between two planar electrodes. Ion-species separation is found to occur, similarly to the results reported for a 80 ns duration plasma-opening-switch experiment of cylindrical geometry, which was not necessarily expected since in the present experiment plasma pushing is more substantial. The separation, in which the light-ion plasma (protons) is reflected while the heavy-ion plasma (carbon) is penetrated by the propagating magnetic-field, is investigated by determining the electron density from the temporal evolution of spectral lines, the nonprotonic ion velocities from line-emission Doppler shifts, and the proton velocity distribution from Doppler shifts of line emissions from hydrogen atoms produced by proton charge exchange. The ion dynamics is shown to be consistent with the acceleration expected from the one-dimensional Hall electric field, based on the previously published magnetic-field and electron density evolutions. Significant acceleration of the nonprotonic ions behind the magnetic-field front is observed. It is found that a significant fraction of the protons acquire a velocity that is more than twice the velocity of the magnetic piston. This phenomenon is shown to result from the time dependence of the accelerating electric field and the broad acceleration region. The lateral motion of the nonprotonic ions is also discussed.

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Section: Proton Velocity Measurementsmentioning

confidence: 84%

Investigation of the ion dynamics in a multispecies plasma under pulsed magnetic fields

et al. 2004

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“…Details of the coaxial configuration can be found in a previous publication. 18 The planar configuration, depicted in Fig. 1, consists of two 14-cm-wide electrodes separated by a 2.5 cm gap.…”

Section: Methodsmentioning

confidence: 99%

Plasma dynamics in pulsed strong magnetic fields

et al. 2004

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Recent investigations of the interaction of fast-rising magnetic fields with multi-species plasmas at densities of 1013–1015 cm−3 are described. The configurations studied are planar or coaxial interelectrode gaps pre-filled with plasmas, known as plasma opening switches. The diagnostics are based on time-dependent, spatially resolved spectroscopic observations. Three-dimensional spatial resolution is obtained by plasma-doping techniques. The measurements include the propagating magnetic field structure, ion velocity distributions, electric field strengths, and non-Maxwellian electron energy distribution across the magnetic field front. It is found that the magnetic field propagation velocity is faster than expected from diffusion. The magnetic field evolution cannot be explained by the available theoretical treatments based on the Hall field (that could, in principle, explain the fast field propagation). Moreover, detailed observations reveal that magnetic field penetration and plasma reflection occur simultaneously, leading to ion-species separation, which is also not predicted by the available theories. A possible mechanism that is based on the formation of small-scale density fluctuations, previously formulated for astrophysical plasmas, may explain these results.

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“…Previous experimental studies of flashboards include a detailed investigation of the plasma flow velocity and uniformity for various driving circuits and flashboard configurations [5] using electrical probes. A recent experiment [9], in which the electron density was determined both by spectroscopic measurements and by electrical probes, showed that electrical probes underestimate the electron density of a flashboard plasma by up to an order of magnitude. A spectroscopic investigation of the electron density, temperature, and plasma composition was carried out on a flashboard driven by a relatively low current through the discharge chains [10].…”

Section: Introductionmentioning

confidence: 99%

Spectroscopic investigations of a dielectric-surface-discharge plasma source

et al. 2000

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Spectroscopic investigations of the properties of a plasma produced by a flashboard plasma source, commonly used in pulsed plasma experiments, are presented. The plasma is used to prefill a planar 0.4-µs-conduction time plasma opening switch (POS). A novel gas-doping technique and a secondary surface flashover plasma source are used to locally dope the plasma with gaseous and solid materials, respectively, allowing for spatiallyresolved measurements. The electron density, temperature, and plasma composition are determined from spectral line intensities and line profiles. Detailed collisional-radiative modeling is used to analyze the observed line intensities. The propagation velocity and divergence angle of various ions are determined from time-of-flight measurements and Doppler broadening of spectral lines, respectively. This allows for distinguishing the secondary plasma ejected from the POS electrodes from the plasma of the flashboard source.

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Study of the effects of the prefilled-plasma parameters on the operation of a short-conduction plasma opening switch

Cited by 15 publications

References 27 publications

Investigation of the ion dynamics in a multispecies plasma under pulsed magnetic fields

Investigation of the ion dynamics in a multispecies plasma under pulsed magnetic fields

Plasma dynamics in pulsed strong magnetic fields

Spectroscopic investigations of a dielectric-surface-discharge plasma source

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