Minisymposium Presentation

In this work we describe a fully kinetic PIC MC (Particle in Cell Monte Carlo) code, BIT1, used for the simulation of plasma, neutral, and impurity particle transport in the tokamak edge [2]. BIT1 has several unique features enabling near ab-initio modeling of nonlinear processes in the plasma edge: it can resolve the smallest time and space scales and still simulate large systems, such as the tokamak Scrape-off Layer (SOL) and can track very slow and fast particles with high accuracy, Vmax/Vmin > 1000 and so on. As an example, we present several recent results obtained from BIT1 simulation of the plasma edge of existing and future tokamaks.To address the main drawback of such modeling, which has extremely long simulation times, such as the ITER SOL BIT1 simulation requiring up to 10 million CPU hours, equivalent to half a year of simulation time under realistic conditions, we initiate the development of an exascale version of the BIT1 under the Horizon project Plasma-PEPSC [3]. Furthermore, we outline the BIT1 exascale porting process, which includes algorithmic restructuring, GPU porting, and implementation of highly scalable parallel I/O using openPMD. [1] https://www.iter.org/ [2] D. Tskhakaya, Plasma Phys. Control. Fusion, 59, (2017)[3] https://plasma-pepsc.eu/