Non-Maxwellian Ion Distributions Caused by Neoclassical Heat Conduction

It is shown that in tokamaks with neoclassical banana-regime heat conduction and ion self-collisions dominant for energy scattering, the distribution tail diffuses outwards radially and downwards in energy maintaining a constant effective temperature ${\left(\frac{-\partial \ln f_i}{\partial \epsilon }\right)}^{-1\mathrm{}}$, as observed in some experiments.