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Title: Measurements of the volt-ampere characteristics and the breakdown voltages of direct-current helium and hydrogen discharges in microgaps

The discharge phenomena for micro meter gap sizes include many interesting problems from engineering and physical perspectives. In this paper, the authors deal with the experimental and theoretical results of the breakdown voltage and current-voltage characteristics of the direct-current helium and hydrogen discharges. The measurements were performed at a constant pressure of around one atmosphere, while varying the gap size between two parallel plane tungsten electrodes between 1 μm and 100 μm. From the measured breakdown voltage curves, the effective yields and the ionization coefficients were derived for both gases. Present data for the ionization coefficients correlate with the data obtained for the breakdown voltage curves measured for fixed 100 μm interelectrode separation. The current-voltage characteristics were plotted for the various gap sizes illustrating the role of the field emission effects in the microgaps. Based on the Fowler-Nordheim theory, the enhancement factors were determined. The gap spacing dependence of the field emission current can be explained by the introduction of two ideas, the first being a space charge effect by emitted electrons, and the second a change in the breakdown mechanism. Experimental results, presented here, demonstrate that Townsend phenomenology breaks down when field emission becomes the key mechanism affecting the breakdown and deformingmore » the left hand side of the breakdown voltage curves.« less
Authors:
;  [1] ; ;  [2]
  1. Department of Experimental Physics, Comenius University, Mlynskadolina F2, 84248 Bratislava (Slovakia)
  2. Institute of Physics, University of Belgrade, P.O. Box 57, 11080 Belgrade (Serbia)
Publication Date:
OSTI Identifier:
22299715
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 21; Journal Issue: 10; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; BREAKDOWN; DIRECT CURRENT; ELECTRIC CONDUCTIVITY; ELECTRIC POTENTIAL; ELECTRONS; FIELD EMISSION; FOWLER-NORDHEIM THEORY; HELIUM; HYDROGEN; SPACE CHARGE; TUNGSTEN