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Stability of very-high pressure arc discharges against perturbations of the electron temperature
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Authors
Advisor(s)
Abstract(s)
We study the stability of the energy balance of the electron gas in very high–pressure plasmas
against longitudinal perturbations, using a local dispersion analysis. After deriving a dispersion
equation, we apply the model to a very high–pressure (100 bar) xenon plasma and find instability
for electron temperatures, Te, in a window between 2400 K and 5500-7000 K, depending on the
current density (106
–108 A/m2
). The instability can be traced back to the Joule heating of the
electron gas being a growing function of Te, which is due to a rising dependence of the electron atom collision frequency on Te. We then analyze the Te range occurring in very high–pressure
xenon lamps and conclude that only the near-anode region exhibits Te sufficiently low for this
instability to occur. Indeed, previous experiments have revealed that such lamps develop, under
certain conditions, voltage oscillations accompanied by electromagnetic interference, and this
instability has been pinned down to the plasma-anode interaction. A relation between the
mechanisms of the considered instability and multiple anodic attachments of high-pressure arcs is
discussed.
Description
Keywords
Very-high pressure arc discharges Electron temperature . Faculdade de Ciências Exatas e da Engenharia
Citation
Benilov, M. S., & Hechtfischer, U. (2012). Stability of very-high pressure arc discharges against perturbations of the electron temperature. Journal of Applied Physics, 111(7), 073305. DOI: 10.1063/1.3702469
Publisher
American Institute of Physics