1999 IEEE International Conference on Plasma Science,
Monterey, California, USA, June 20-24, 1999

(ISBN 0-7803-5224-6)

Two-temperature, two-dimensional modeling of cathode hot spot formation including sheath effects - application to high pressure xenon arc lamps

J Wendelstorf, H Wohlfahrt und G Simon

[5P03, p.240, abstract published only:]
One of the fundamental problems in high pressure gas discharges is the prediction of plasma/cathode interaction. The cathode hot spot temperature determines electron emission and plasma formation. The critical physical processes in the cathode/plasma system are electron emission, heat conduction and the formation of the cathodic boundary layers and the thermal plasma expansion zone. The nonlinear interaction of these phenomena is decisive for important technological parameters like electrode erosion and peak plasma temperature, e.g. in HID-lamps. The self consistent single temperature model [1] is extended to allow for deviations of electron temperature Te from heavy particles temperature Th. Modeling of the cathode-plasma region now includes the following physical processes self consistently: Assuming a stationary discharge in cylindrical symmetry, the model is applied to high pressure xenon short arc lamps with operating pressures of 1-4 MPa and currents of several ampere. The temperature split region is found to extend over 200Ám in front of the cathode surface. Sheath effects critically influence the hot spot temperature of the cathode. This modeling approach can be regarded as an important step in the development of predictive models of thermal plasma gas discharges like high pressure (arc) lamps. Financial support by the BMBF (Germany) under Contract No.13N7105 is gratefully acknowledged.
[1] J Wendelstorf et.al., 8th Int. Symposium Science & Techn. Light Sources (LS-8), Greifwald, 1998, M01, p.382
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Letzte Änderung: 20.7.1999
URL: http://www.wendelstorf.de/doc/1999/jw4601.99/index.html
Kontakt: Jens@Wendelstorf.de