抄録
The ion-temperature-gradient (ITG) mode instability in sheared slab geometry in the presence of a mesoscale magnetic island is investigated with a focus on the short-wavelength regime (kyρi > 1). We found that a static magnetic island causes radial and poloidal modes to couple and therefore plays a stabilizing role by allowing energy transfer from unstable modes to stable modes. However, for large island widths, the short-wavelength ITG mode becomes strongly destabilized and tends to dominate over the standard ITG mode (kyρi ≅ 0.5). A reduced model is proposed in this paper to understand this destabilization mechanism.
