Multi-scale interaction among neoclassical tearing mode and drift wave turbulence

Abstract. The multi-scale interaction among the tearing mode and the drift wave is investigated using reduced MHD model including the electron viscosity. It is newly found that the fluctuating bootstrap current in the Ohm’s law gives rise to a new instability for the regime where the tearing mode is stable. The stability depends on the dissipations and kinetic effects. This result implies that for some parameter regime where Δ’ is negative, the seed island may not be needed to drive the neoclassical tearing mode. The nonlinear simulations with multihelicity modes are performed for the q profile where the (2,1) tearing modes is unstable and for the optimized q profile where all tearing modes are stable. These results are compared with each other.