Radially global $\delta f$ computation of neoclassical phenomena in a tokamak pedestal

Abstract

Conventional radially-local neoclassical calculations become inadequate if the radial gradient scale lengths of the H-mode pedestal become as small as the poloidal ion gyroradius. Here, we describe a radially global $\delta f$ continuum code that generalizes neoclassical calculations to allow stronger gradients. As with conventional neoclassical calculations, the formulation is time-independent and requires only the solution of a single sparse linear system. We demonstrate precise agreement with an asymptotic analytic solution of the radially global kinetic equation in the appropriate limits of aspect ratio and collisionality. This agreement depends crucially on accurate treatment of finite orbit width effects.

References in corpus (2)

• Local and global Fokker-Planck neoclassical calculations showing flow and bootstrap current modification in a pedestal
• New velocity-space discretization for continuum kinetic calculations and Fokker-Planck collisions

Cited by in corpus (7)

• Comparison of particle trajectories and collision operators for collisional transport in nonaxisymmetric plasmas
• Plasma rotation from momentum transport by neutrals in tokamaks
• Edge Momentum Transport by Neutrals: an Interpretive Numerical Framework
• Global effects on neoclassical transport in the pedestal with impurities
• Edge rotation from momentum transport by neutrals
• Neoclassical flows in deuterium-helium plasma density pedestals
• Isotope and density profile effects on pedestal neoclassical transport