Energetic-ion-driven instabilities and transport: Multi-time-scale simulations, validation, predictions and insights

The resonant excitation of MHD waves plays an important role for the confinement and transport of energetic ions in MCF plasmas. This presentation reports recent advances that were made in simulating these wave-particle interactions numerically using a hybrid model, which includes realistic beam ion sources and beam-bulk collisions, so that it is valid over a wide range of time scales: from Alfvenic oscillations (μs scale) to collisional slow-down (>100 ms). In order to be able to simulate the long-time evolution on available supercomputers, the so-called multi-phase method is employed. Although it was originally intended to improve the accuracy of numerical predictions in cases where the system settles in a relatively steady state and study aspects such as profiles resiliency, it turns out that this method even allows us to reproduce multiple cycles of so-called abrupt large-amplitude events (ALE), as seen in JT-60U. The latest insights on ALE physics obtained with such simulations are discussed.2018 Korean Physical Society (KPS) Fall Meeting, Pioneer Symposium 8: “Data-based Plasma Science and Simulation for the Computer Aided Design