Neoclassical Bootstrap Current Comparison

The Models

NeoWes is a simple neoclassical module intended for circular models, using a set of formulae from Wesson's textbook Tokamaks. NeOS is Olivier Sauter's package using a set of fitting coefficients to Fokker-Planck results. NeoArt is the multi-species neoclassical code from Arthur Peeters. Here we do a simple comparison.

In a model using simple profiles and the equilibrium code BDSEQ (circular boundary surface, shifted-circle flux surfaces) we compare the run of the bootstrap current and conductivity in the two models as a function of which is defined as the normalised toroidal flux radius rho_tor_norm in the CPO. An electron-proton plasma with equal temperatures and densities is assumed with

with parameters Of course, Note that in the CPOs is times jphi (ie, it is the covariant component). The sign conventions for and follow ITER (out of the poloidal plane, on the right of the symmetry axis, from the point of view of an observer in the toroidal midplane outside the tokamak).

The necessary CPO input to BDSEQ is

equilibrium%global_param%toroid_field%b0
equilibrium%global_param%toroid_field%r0
equilibrium%eqgeometry%a_minor
equilibrium%profiles_1d%rho_tor
equilibrium%profiles_1d%pressure
equilibrium%profiles_1d%jphi

The first three are respectively, and rho_tor is on the coreprof grid. The pressure and current are found from also on the coreprof grid.

The following graph gives the results of the comparison. The solid lines are from NeoArt, the dashed ones from NeoWes, and the dot-dashed ones from NeOS. In the context of such a circular model the results are in good agreement. On the conductivity, we don't have the one from NeoArt yet so the other two are shown.