Verification and RW Validation of Collision Models for the Edge Gyrokinetic Code COGENT

Seth Davidovits, Princeton University

Understanding the edge of tokamak plasmas is an important problem in fusion studies. The edge presents a number of simulation challenges, with its complex geometry, large amplitude turbulent fluctuations, and the fact that it spans both collisionless and collisional regions. COGENT is a full-f continuum gyrokinetic code being developed to tackle these problems, using a fourth-order conservative finite volume discretization and mapped multiblock grid technology to handle tokamak edge geometry. COGENT implements a number of collision models containing various levels of physics, such as a simple Krook operator, Lorenz collisions, and a linearized-model Fokker-Planck operator. Here we present preliminary verification and validation results for these collision models.

Abstract Author(s): Seth Davidovits, Phil Colella and the COGENT team