Everyone familiar with Godzilla should know of his iconic blue atomic breath. I've seen "theories" (technically not really theories) on how Godzilla's atomic breath works on the web. However, what about a green atomic breath? Could there be a plausible explanation for a green-hued, flame-like heat ray based on nuclear radiation?
I've seen comments saying Godzilla's atomic breath could be made of plasma, but the problem with this one in particular is that green is not associated with thermal emission (plus, the Japanese Godzilla's atomic breath gets hotter as it goes from blue to red, which is the exact opposite behavior of real-life plasma).
I've found examples through Google Images of real-life plasma jets becoming green after being injected with chemicals like boron and copper. I then read that Type II supernovae can produce boron and that supernovae can also produce copper. That started to give me ideas, but as far as I know, supernovae have not been observed to be green.
Follow up: Could there be a plausible explanation for lighting water on fire through non-chemical means?