However this is about dark matter as well. Once we shut this bulb down the vacuum will continue to glow in a dark room for nine hours before the trapped photon energy is finally discharged. At the same time, the temperature of the tube using a laser thermometer gives us a value below the measuring range of the device itself or -20 degrees C. However this not what is felt so it is a measurement of the radiation itself which likely lacks a significant distribution spread allowing itself to be detected correctly. That is why I think it is coherent. Regardless, we are running a cold spark and the whole system handles 50,000 volts with no noticeable heat.