Ion Thermal Conductivity in a Helical Toroid

Numerical calculations of the ion thermal conductivity in helical toroidal (torsatron) magnetic configurations show the presence of a plateau regime extending over two orders of magnitude in collision frequency, $\nu$. The value of the ion thermal conductivity is approximately equal to the neoclassical plateau value for an equivalent torus without helical modulation. The predicted adverse $\frac{1}{\nu }$ behavior due to ripple trapping is not seen.