Wiktionary
n. an arc struck between the tip of a carbon electrode and a piece of metal being welded
WordNet
n. has carbon electrodes [syn: carbon arc lamp]
Usage examples of "carbon arc".
The diplomats didn't seem to want to relive their youth under the carbon arc at that time of the day.
In the helmet it was a yellow spark, without detectable disc, like a carbon arc through a lens-system set at infinity.
Wastes removed would be destroyed by passage through a carbon arc after innumerable previous sterilizing processes.
An electrical motor to lift and pull things, a light called the carbon arc that can pierce the night, a way of coating things with a thin layer of metal, and many more.
I said carbon arc lights, because that's the method that's used in engineering, but of course a longer exposure to sunlight or any other form of light would also have the same effect.