At mid-radius in a tokamak resembling ASDEX Upgrade the inverse aspect ratio is and…

PHYSICS · Subjective · Fermi University Physics · Plasma Physics · Kinetic theory, collisions and transport · Kinetic theory, collisions and transport

Plasma Physics, Ch Transport across and along the field: ambipolar, classical, neoclassical and anomalous

Problem

At mid-radius in a tokamak resembling ASDEX Upgrade the inverse aspect ratio is

\epsilon = 0.30

and the safety factor is

q = 1.8

. The local ion Larmor radius is

r_{Li} = 1.5\,\mathrm{mm}

and the local ion collision time (Braginskii's

\tau_i

) is

\tau_i = 2.0\times10^{-3}\,\mathrm{s}

. Estimate the neoclassical ion heat diffusivity in the banana regime, using

\chi_i^{\rm neo} \sim q^2\epsilon^{-3/2}\frac{r_{Li}^2}{\tau_i}.

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