Ball lightning plasma and plasma arc formation during the microwave heating of carbons

Microwave heating can be used to promote heterogeneous reactions with carbon materials, mainly because of the heating mechanism involved in microwave radiation and the phenomenon known as microplasmas. This work presents photographic evidence of plasma formation when different carbon materials are subjected to microwave heating. Two different kinds of plasmas were observed: ball lightning and arc discharge plasmas. The intensity of the plasmas in the less ordered carbon was significantly higher at the beginning of the process.