Gyrokinetic simulation of edge pedestal in a middle-sized tokamak

In the present fusion devices, radial transport of particle s and heat is mainly determined by plasma turbulence. Due to its complexity, high performance computing, either with particle or Vlasov codes, plays a major role in plasma turbulence research. While the neoclassical transport is often only a minor part of the total radial transport, the neoclassical physics may indirectly have significant effec t on transport level as, at the edge, the neoclassical radial electric field alone can be steep enough to suppress turbulence [1, 2]. As the analytic neoclassical theory is not valid at the edge where the gradients are steep compared to orbit width, particle simulations are required to obtain proper fields. Also, within one orbit width from last closed flux surface the direct ion orbit losse s may have important effect on the radial electric field. In this paper, we use the particle simulation code Elmfire [3] , which includes both neoclassical effects and electrostatic turbulence. Such simulation s are very CPU consuming which limits the simulations to middle-sized tokamaks. The main code development effort reported here is to include scrape-off-layer (SOL) in order to study edge-core coupling which according to experiments plays an important role in obtaining low-to-high confinement transition which is crucial for future fusion devices such as ITER. The gyrokinetic full-f code Elmfire