A Note for Neoclassical Transport in the Pfirsh-Schlüter Regime of Ultra-Low-Aspect-Ratio Tokamak

Abstract

In the ultra-low-aspect-ratio tokamak, neoclassical viscosity plays a role to enhance the neoclassical transport such as bootstrap current and ion thermal conductivity in the Pfirsch-Schlüter regime. The geometrical factor <(n ∇B)²> for calculating the viscosity [K.C. Shaing et al., Phys. Plasmas 3, 965 (1996)] shows divergent tendency for assumed sequences of numerical MHD equilibria when the aspect ratio is reduced to 1.05, where n=B/B and B is the equilibrium magnetic field.