Effects of orbit squeezing on ion transport processes close to magnetic axis

摘要

It is shown that ion thermal conductivity close to the magnetic axis in tokamaks is reduced by a factor of (vert bar)S(vert bar)(sup 5/3) if (M(sub i)/M(sub e))(sup 2/3)(T(sub e)/T(sub i))(sup 4/3)/(vert bar)S(vert bar)(sup 5/3) (much gt) 1. S is the orbit squeezing factor, M(sub i)(M(sub e)) is the ion (electron) mass, and T(sub i)(Te(sub e)) is the ion (electron) temperature. The reduction reflects both the increase of the fraction of trapped particles by a factor of (vert bar)S(vert bar)(sup 1/3), and the decrease of the orbit size in units of the poloidal flux (psi) by a factor of (vert bar)S(vert bar)(sup 2/3).