Modeling of neoclassical tearing mode stabilization by electron cyclotron heating and current drive in tokamak plasmas

Abstract

An integrated numerical system is established to model time-dependent behavior of the neoclassical tearing mode (NTM) in a tokamak which solves the modified Rutherford equation (MRE) by coupling with plasma transport, equilibrium, heating and current drive. The MRE is formulated in a simple form to be well-suited for time-dependent simulations including a predictive purpose for the feedback controller design by coupling the electron cyclotron effect self-consistently. In particular the electron cyclotron heating (ECH) effect is newly included to the MRE in addition to the electron cyclotron current drive (ECCD) effect to investigate their impact to stabilize the NTM. The integrated numerical system is applied to experiments for benchmarking in which NTMs are stabilized by ECCD and by ECH at ASDEX Upgrade and TCV, respectively. The impact of ECCD and ECH on stabilizing NTMs is identified in the simulations.