2-D/3-D visualization of MHD instabilities and turbulence on KSTAR and WEST

Abstract

Magnetohydrodynamic (MHD) instabilities and turbulence based trasport physics in tokamak plasma are essentially multi-dimensional, and imaging diagnostics with high temporal and spatial resolution are thus necessary for comprehensive understanding of the phenomena. The electron cyclotron emission imaging (ECEI) and microwave imaging reflectometry (MIR) diagnostics installed on KSTAR measure 2-D electron temperature and density fluctuations. Both imaging diagnostics provide invaluable understanding of the interesting phenomena, such as the edge-localized modes (ELMs) and their interaction with turbulent eddies generated by Resonant magnetic perturbation, modified sawtooth instability coexisting with higher harmonics (m/n=2/2, 3/3, 4/4, …) due to current perturbation. A new ECEI system for WEST device is in final development stage, and expected to be installed on WEST in early 2018. Comparative study of the 2-D ∆Te images obtained from KSTAR and WEST devices would provide the role of tungsten impurity on the dynamics of MHD instabilities, which will be essential for successful operation of ITER.