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Abstract. Neoclassical tearing modes (NTM) can be responsible for beta
limitation in long-pulse ITER discharges. The excitation and growth of NTM
are governed by the competing bootstrap current, polarization current and
so-called effects. Also, the magnetic well and Electron Cyclotron
Current Drive (ECCD) can stabilize the NTM. We study analytically and
numerically all the effects with a particular emphasis on the polarization
current in the analytical part of our study. We show that the polarization
current description requires a generalized transport theory including the
hyperviscosity, electron pressure gradient and, as well, the finite ion
Larmor radius effects in the perpendicular current. The profile function
nonstationarity must be taken into account for calculation of the island
rotation frequency. Results of numerical simulation of NTM suppression by
modulated ECCD in ITER are presented.
IAEA 2001