Ascertain convergence of simulated parallel diffusion coefficients

Ascertain whether, in the weak slab and composite turbulence setups considered, the parallel diffusion coefficient computed from full-orbit simulations has converged to a constant value, and determine appropriate convergence diagnostics or runtime requirements.

Background

To compare methods against quasi-linear theory (QLT), the authors use QLT to estimate scattering times rather than simulation-derived parallel diffusion coefficients. They explicitly note uncertainty about convergence of the simulation-derived coefficients despite long runtimes, implying a need for robust criteria to judge convergence in practice.