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Indexed by:会议论文

Date of Publication:2017-07-01

Page Number:1

Key Words:plasma perturbation;underlying mechanism;differential rotations

Abstract:Plasma perturbations from the core and/or boundary regions of tokamaks can provide seed islands for the excitation of neo-classical tearing modes(NTMs) with the negative linear instability parameter of the classical tearing mode.In this work,by means of reduced magnetohydrodynamic simulations,we numerically investigate the nonlinear evolution of multi-helicity NTMs in tokamak plasmas with these two types of plasma perturbations with different boundary conditions.In the first case of initial plasma perturbations from the core region with zero boundary condition,the-stable property of seed island triggered NTM with negative instability parameter is verified in the single helicity simulation.In the second case of initial plasma perturbations from the boundary region with nonzero boundary condition,as the amplitude of plasma perturbations on the boundary increases,the mode with negative instability parameter gradually changes from the driven-reconnection state to the NTM state,accompanying with an enhancement of ...