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Publication
Formation of stationary and transient spots on thermionic cathodes and its prevention
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Advisor(s)
Abstract(s)
Spots on cathodes of high-pressure arc discharges induced by a rapid increase in the arc
current are studied numerically and experimentally. Appearance of stationary and transient
spots is analysed in the context of the general pattern of steady-state modes of current transfer
to thermionic cathodes and their stability. Transient spots are studied in experiments with
COST-529 standard lamps. Modelling and experimental results are in reasonable agreement.
A method to prevent formation of transient spots on cathodes of high-pressure arc discharges
by means of short negative rectangular current pulses is proposed and validated both
numerically and experimentally. Experimental indications are found that the main mechanism
of blackening of burners of HID lamps that accompanies appearance of transient cathode spots
is evaporation of the cathode material and not sputtering.
Description
Keywords
Arc discharges Stationary and transient spots Thermionic cathodes . Faculdade de Ciências Exatas e da Engenharia
Citation
Almeida, P. G. C., Benilov, M. S., & Cunha, M. D. (2008). Formation of stationary and transient spots on thermionic cathodes and its prevention. Journal of Physics D: Applied Physics, 41(14), 144004. DOI: 10.1088/0022-3727/41/14/144004
Publisher
IOP Publishing