Gyro-Kinetic Simulation of Ion Temperature Gradient Driven Drift Wave Instability in the Presence of a Magnetic Island

摘要

The ion temperature gradient (ITG) mode instability in the presence of a meso-scale magnetic island using a gyro-kinetic simulation code is investigated. The difference between a model with full gyro-kinetic effects and one reduced to first order—is emphasized. We find that a magnetic island causes radial and poloidal modes to couple with each other, thus play a stabilizing role by allowing energy transfer to stable modes. For larger island sizes, new rational surfaces appear, which again may excite destabilization. In contrast to gyro-O(1) and gyro-fluid simulations, full gyro-kinetic simulation have a larger mode spectra due to short-wavelength effects, which limits energy transfer and thus stabilization is relaxed.