Capacitive influence

In this experiment I used an HF high-voltage (~20 kV) power source to excite relatively weak filamentary discharges inside the burner of a Philips Xeneco automotive lamp. Despite the lamp's 16 bar xenon fill, it is relatively easy to generate such discharges because of the field enhancement at the lamp's sharp internal electrodes, and the presence of a weak argon glow plasma in the outer bulb (barely visible) which acts as an antenna and a UV enhancer. Here I connected the HV output cable of the power supply to the left lead while the ground connector is visible on top of the lamp. The bluish glow comes from the fluorescence of the UV-stop outer jacket made of cerium-doped fused silica.