Plasma diagnostics in Hg free short arc lamps for automotive lighting

The intention of the work was to develop a mercury free lamp for automotive lighting. For this purpose a new lamp design was chosen consisting of a sapphire capillary combined with ceramic parts. The lamps contain metal halides and between 1 and 20 bar Xe. They are operated with electronic ballast at a power of about 30 W. Besides an optimization of the tube materials thermography and plasma diagnostic were performed to understand the processes inside the lamp and to find optimized operation conditions. In addition to experimental diagnostics a simulation of Na spectral lines was performed to verify plasma temperature profiles and partial pressures.