Short arc high intensity discharge (HID) lamps have many applications, including the 35W D2 lamp for automotive headlights. The challenges in modelling such a lamp are e.g. the important plasma-electrode-interaction, time dependence (electrodes change with 400 Hz from anode to cathode phase and vice versa), or the complex plasma composition (Xe, Hg, Nal, Set). Additionally the electrodes might change their well defined tip geometry during operation causing substantial changes in electrode temperature or electrode fall voltages [3]. This paper wants to address all these questions and compare the results of the numerical simulations with measurements of plasma and electrode temperatures. These results are very important for the principal understanding of DC and AC HID lamps including the effect of different electrode geometries and the handling of complex plasma compositions. Furthermore they can lead to improved or new types of HID lamps.
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