NESO-Tokamak

[jwscook]

Take the best bits of https://github.com/ExCALIBUR-NEPTUNE/nektar-diffusion-ambipolar for the oblique BCs and cylindrical coordinate systems and https://github.com/ExCALIBUR-NEPTUNE/nektar-driftwave for the more complete equations inlcuding temperature and vorticity and put them into https://github.com/ExCALIBUR-NEPTUNE/NESO-Tokamak as a NESO mini-app (i.e. NESO is a gitsubmodule).

@will-saunders-ukaea will complete the 2D composites interactions required for 2d particles in Nektar.

@SMijin to contribute some Reactions to this eventually

[futtersack]

Idea would be to have a mini-app allowing different models, based on full-drift-wave but simplified eg. :

1. Ti from equation OR Ti = Te ( 1+alpha) OR Ti = Te = T0 (ie. alpha = 0 with following Te = T0)
2. Te from equation OR Te = T0 OR Te = (Phi - Lambda) / ln N (boltzman)
3. V// from equation OR V// = k_par/N grad// N OR V// = 0 (SLAB 2D)
4. Phi from equation Lapl(Phi) = -W or Phi = Lambda + Te ln N
5. v_perp = -grad Phi x B / B2 always

Current implementation of drift-wave is cartesian with B along Z, but we want to run it on the MASTU mesh in the poloidal plane with varying B, hence the need of anisotropic diffusion for the parallel/poloidal part