Detection of neoclassical tearing modes in demo using the electron cyclotron emission

Tokamak plasmas with high fusion performances are prone to magnetohydrodynamic (MHD) low m,n instabilities which may affect the energy and particle confinement time and possibly lead to disruptive plasma termination. In presently operating tokamaks high space resolution (similar to 2 cm) and high time resolution (0.01-0.1 ms) electron cyclotron emission (ECE) diagnostics are embedded in the control loop finalized to MHD control, often in synergy with pick-up coils sensitive to the magnetic fluctuations. Microwave diagnostics have plasma facing components (antennas) that are electrically passive, have metal body and are mechanically fixed. Such characteristics of robustness and reliability are a promising feature but the diagnostic performances in term of achievable space resolution and profile coverage for prompt detection of instabilities in the high temperature and density conditions of the DEMO reactor need to be assessed. The results of such assessment based on the EU-DEM01-2015 scenario show that extraordinary mode ECE in 2nd harmonics seems to have enough space resolution in the region interested by 3/2 and 2/1 NTMs. (C) 2017 Published by Elsevier B.V.