Phase-Locking Of Magnetic Islands Diagnosed By Ece-Imaging

Millimeter-wave imaging diagnostics identify phase-locking and the satisfaction of 3-wave coupling selection criteria among multiple magnetic island chains by providing a localized, internal measurement of the 2D power spectral density, S(omega, k(pol)). In high-confinement tokamak discharges, these interactions impact both plasma rotation and tearing stability. Nonlinear coupling among neoclassical tearing modes of different n-number, with islands not satisfying the poloidal mode number selection criterion < m, m', m - m'>, contributes to a reduction in core rotation and flow shear in the vicinity of the modes. (C) 2014 AIP Publishing LLC.