Transport in ITER-like plasmas in neoclassical, fluid and gyrokinetic descriptions

Abstract. Turbulent and neoclassical transport in a reference hybrid-mode ITER plasmas is studied using a hierarchy of modeling tools. Transport from ITG/TEM instability is studied with nonlinear gyrokinetic simulations and compared with results from quasilinear fluid and gyro-Landau fluid models. Simulations include full kinetic ion and electron dynamics, although a pure-D mixture is assumed for the bulk ions. We perform the comparison over the full region interior to the pedestal, and derive all simulation parameters from the reference profiles. These comparisons form the starting point for future predictive modeling using direct gyrokinetic simulations. For reference, neoclassical transport of particles and energy is also computed using a new first-principles kinetic code with an advanced multi-species collision operator. Both quasilinear models tend to stay roughly within a factor of two of the reference gyrokinetic simulations, which is remarkable given that they are at least four orders of magnitude faster than direct nonlinear simulation.