Pseudospark switches-technological aspects and application

In the following, we report tests of a semiconductor as electrode material in a pseudospark switch, which is a low pressure gas discharge switch. Polycrystalline SiC or BC disks with central apertures were embedded in molybdenum outer electrodes in a typical single stage pseudospark geometry. The maximum voltage applied was 15 kV. Tests were done with peak currents from 50 up to 500 kA at pulse lengths of a few microseconds. We found no difference in the voltage breakdown or the rise in current when compared to conventional metal electrodes such as molybdenum or tungsten. Fast shutter photographs showed that the discharge burns in an intense column at the center and is distributed very homogeneously over the SiC surfaces. Neither cathode nor anode spots were observed. Small sparks occurred at the metal-carbide interface after current zero, which led to a reignition in the second current half-wave. An estimation after the tests showed an erosion rate of about 5 g/C approximately one order of magnitude lower than in metals. We assume that the current is transported in a thin surface layer. Ion bombardment in the pseudospark discharge heats this layer to more than 2000 K, lowering the specific resistance. The negative temperature-resistance characteristic means that cathode spots are avoided.

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“…This may be contrasted with the loss in graphite ͑20Ϯ5͒ g/C or tungsten ͑110Ϯ5͒ g/C. 5 The same results were obtained with BC. ͑Fig.…”

Section: Resultssupporting

confidence: 53%

The use of carbides as electrode material in a pseudospark switch

Gortler

Schwandner

Frank

et al. 1996

Journal of Applied Physics

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“…Laser-induced ionization is a key step in many applications of ultrashort laser pulses, including laser ablation [1,2], laserinduced breakdown spectroscopy (LIBS) [3,4], fast electric switching [5,6], or the control of high-voltage discharges [7][8][9] and lightning [10].…”

Section: Introductionmentioning

confidence: 99%

Optimal laser-pulse energy partitioning for air ionization

et al. 2016

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We investigate the pulse partitioning of a 6.3-mJ, 450-fs pulse at 1030 nm to produce plasma channels. At such moderate energies, splitting the energy into several subpulses reduces the ionization efficiency and thus does not extend the plasma lifetime. We numerically show that when sufficient energy to produce multifilamentation is available, splitting the pulse temporally in a pulse train increases the gas temperature compared to a filament bundle of the same energy. This could improve the mean free path of the free electrons, therefore enhancing the efficiency of discharge triggering.

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“…Much work has been done on gas lasers. There are several usable articles in the literature 5 , 6 , 7 , 8 . LSDI people say that LN2 would be used to cool a CO laser 9 A more efficient system may be a mode locked seed driving an amplifier.…”

Section: Adt Dtmentioning

confidence: 99%

Laser stripping of relativistic H{sup {minus}} ions with practical considerations

Tomlin¹

1995

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Pseudospark switches-technological aspects and application

Cited by 65 publications

References 21 publications

The use of carbides as electrode material in a pseudospark switch

The use of carbides as electrode material in a pseudospark switch

Optimal laser-pulse energy partitioning for air ionization

Laser stripping of relativistic H{sup {minus}} ions with practical considerations

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