The goal of the proposed research is to develop a scalable multiscale approach that would provide the means for first-ever global three-dimensional simulations of turbulence, magnetic reconnection, ion energization and shocks in confined magnetized plasmas, where characteristic scales of interest are driven by ion kinetic and Hall effects. This effort is proposed to be carried out with our new asynchronous hybrid code, HYPERS (Hybrid Particle Event-Resolved Simulator), which has been developed with prior NSF-DOE support. Immediate applications include laboratory plasmas generated with pulsed and RF technology (e.g., spheromaks, ion beams, field-reversed configurations), while tokamak plasmas with a significant fraction of energetic ion species are viewed as the next target. HYPERS differs from the standard hybrid (kinetic ions and massless fluid electrons) codes in the way simulation is performed. The code does not step variables synchronously in time but instead performs their time integration by executing discrete events: explicit asynchronous updates of particles and fields – Discrete-Event Simulation (DES). These updates are carried out as frequently as dictated by local physical and geometric time scales. Contrary to implicit solutions that suppress fast scales globally everywhere in the simulation domain, HYPERS accurately treats multiple temporal scales with DES. This approach has already led to speedups of up to several orders of magnitude for various problems. There are significant differences between hybrid-PIC (where all ions are treated kinetically) and hybrid-MHD (where the bulk plasma is described by MHD equations and minority ions species are treated kinetically) simulations in weakly collisional regimes. This work will bridge the gap between compute-intensive hybrid-PIC and MHD simulations by enabling accurate and CPU-efficient description of non-MHD physics in entire plasma devices such as the SSX plasma wind tunnel, LAPD, FRCs and tokamaks.
