A Large-Aspect-Ratio Multiscale Pedestal

Understanding of the behaviour of tokamak pedestals is critical to forging a path towards efficient fusion reactors. Existing models [1] of the pedestal region are focused on modelling experiment. These models have achieved great success but some of the underlying physics remains obscure.
Hence, in this work a first-principles approach to the problem is taken. We start from the equations of [2], and construct solutions in the large-aspect-ratio limit. We approximate the fluxes within the pedestal as strongly-driven, critically-balanced turbulence similar to [3]. We support this with nonlinear simulations of the inter-ELM turbulence equations of [2] using GS2 [4]. This results in an inter-ELM equilibrium including in-out asymmetry, poloidal flows, and finite radial electric fields.
We explore the linear theory of such equilibria - both stability to ELM-like perturbations and the theory of slower oscillations.

[1] Snyder, P.B. et. al. Nucl. Fusion 51, 103016.
[1] Abel, I. G. & Hallenbert, A. J. Plasma Phys. vol. 84, 745840202
[2] Barnes, M., et. al. Phys. Rev. Lett. 107, 115003
[3] Wilkie, G., Highcock, E. and Dorland, W. Private Communications