Plasma

[gerkin]

Why does the plasma core inside a TOKAMAK fusion reactor burn colour less (totally invisible) and the outer edges burn white.

[dawkins]

Just a guess but has it got something to do with instabilities at the boundary edge:

http://www.nature.com/nphys/journal/v2/n6/full /nphys312.html

[dawkins]

and I should also of said:

do these instabilities release thermal energies?

I am quite ignorant of the correct answer, please don't quote me without checking

[jake-the-peg]

The plasma at the centre is very much hotter than at the edges and radiates in the high ultraviolet and x-ray end of the spectrum.

see at the bottom here for some nice pictures of the effect.

http://www-drfc.cea.fr/gb/fusion/physique/intr o_ipp.htm