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Heating of refractory cathodes by high-pressure arc plasmas: I
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Authors
Advisor(s)
Abstract(s)
A model of the near-cathode plasma layer in a plasma under a pressure of
the order of one or several bars is reconsidered on the basis of recent
theoretical results. Physics of the near-cathode layer is analysed in the range
of near-cathode voltage drops of up to 50 V, in accord to recent experimental
results which have shown that the near-cathode voltage drop in
high-pressure arc discharges may be that high. It is found that a
non-monotony of the dependence of the energy flux density on the surface
temperature at fixed values of the near-cathode voltage drop is caused by
one of the three mechanisms: overcoming of the increase of combined ion
and plasma electron heating by the increase of thermionic cooling as the
plasma approaches full ionization; non-monotony of the dependence of the
ion current on the electron temperature which is caused by the deviation of
the ion current from the diffusion value; rapid increase of the plasma
electron heating which is subsequently overcome by thermionic cooling.
A closed description of the plasma–cathode interaction is obtained by
numerically solving the nonlinear boundary-value problem for the
temperature distribution inside the cathode body. Results of numerical
modelling of the diffuse discharge under conditions of a model arc lamp are
given and a good agreement with the experimental data is shown.
Description
Keywords
Heating of refractory cathodes Refractory cathodes High-pressure arc plasmas Arc plasmas . Faculdade de Ciências Exatas e da Engenharia
Citation
Benilov, M. S., & Cunha, M. D. (2002). Heating of refractory cathodes by high-pressure arc plasmas: I. Journal of Physics D: Applied Physics, 35(14), 1736.
Publisher
IOP Publishing