Difference between fusion plasma and fluorescent lamp plasmas How is the plasma in a compact fluorescent lamp (CFL) different from a plasma in say ITER or the sun? Why does ITER need 100MK and a CFL can work at practically room temperature (apart from the filament)?
Or could ITER also create a plasma by charging the gas inside the reaction chamber but not have enough energy for the reaction, so they heat it directly (microwaves) and charging it would be of no use?
Or is it the degree of ionization the volume of gas has achieved? Like, a CFL has around $x$ ions and a sun plasma has only ions?
 A: ITER needs very high ion temperatures (100M K) so the deuterons and tritium nuclei are fast enough to overcome electrostatic repulsion and undergo thermonuclear fusion. A CFL only needs to have a conductive plasma in order to have an electron current exciting atoms in the gas.
A: A compact fluorescent lamp belongs to the glow discharge plasmas. Usually you have electron densities on the order of $n_e \approx 10^{16}\,\mathrm{m}^{-3}$, electron temperatures on the order of $T_e\approx 1\,\mathrm{eV}$ and ion temperatures being at least an order of magnitude lower. The degree of ionization is $1\,\%$ or lower. The room temperature you were referring to, only applies to the gas temperature and, more or less, to the ion temperature. The electrons are much hotter.
ITER, in contrast, will have plasmas parameters of $n_e \approx 10^{20}\,\mathrm{m}^{-3}$, $T_e\approx T_i \approx 10\,\mathrm{keV}$.
ITER requires such a high temperature because it is meant to investigate nuclear fusion and to achieve fusion you need to overcome the electrostatic repulsion of the nuclei (remember, both are positively charged). A fluorescent lamp, on the other side, just needs enough energy/temperature to achieve breakdown, as @Rod Price has written.
ITER could of course also create lower temperature plasmas, and it will do so for cleaning the wall, but for fusion, those high temperatures are required.
