Progress with the 5D full‐F continuum gyrokinetic code COGENT

COGENT is an Eulerian gyrokinetic code being developed for edge plasma modelling. The code is distinguished by the use of a high‐order finite‐volume (conservative) discretization combined with mapped multi‐block grid technology. Our recent work is focused on the development of a 5D full‐F COGENT version. A numerical algorithm utilizing locally a field‐aligned multi‐block coordinate system is implemented to facilitate simulations of highly anisotropic microturbulence in the presence of a strong magnetic shear. In this approach, the toroidal direction is divided into blocks such that, within each block, the cells are field‐aligned and a non‐matching (non‐conformal) grid interface is allowed at the block boundaries. Here we report on details of the numerical implementation and present preliminary results of verification studies performed for the case of the ion temperature gradient (ITG) instability in a sheared toroidal annulus geometry.