I think the temperature inside the light is extremely hot, hence the plasma. It is very small, however, and I doubt they would be difficult to cool. They only run on 250 watts and most of the energy is converted to light, not heat. This is awesome, just wait for these puppies to go mainstream.

plasma
Chong Version 2.0 Reviewed by Chong Version 2.0 on . Luxim's new plasma lights According to this post, a company named Luxim has come out with lighting that's 10 times as efficient as incandescent, and 2 times as efficient as LEDs. Also, because the light uses superhot plasma to make light, the spectrum is almost identical to that of the sun. CNET has a video of the lights here. Looks like an awesome light source. The only question left is 'how much'? Rating: 5