Energy Confinement in Self-Organized Tokamak Plasma (without Transport Barriers)

The phenomenon of improved energy confinement during radiative cooling at the plasma edge was studied experimentally in the T-10 tokamak. It was shown that the effect is independent on the kind of radiating gas. No substantial differences were observed using Ne, which radiates at two-thirds of the plasma radius, or He, which radiates at the very edge. This phenomenon is explained in frames of nonequilibrium thermodynamics. In a self-organized plasma, the energy balance is described by a Smoluchowski-type equation, where the plasma thermal conductivity and its functional dependence on the intensity of the heat flux, perturbing the pressure profile, is determined from experiment.