Electron cyclotron emission imaging system for 2D electron temperature fluctuation measurements in WEST

Abstract An electron cyclotron emission imaging (ECEI) system was developed and successfully commissioned on the WEST tokamak to perform 2D measurements of the electron temperature fluctuations. The system follows established ECEI configurations, utilizing a 24-channel detector array coupled with 192-channel intermediate frequency (IF)/video modules, a frequency-tunable local oscillator (LO) source, imaging and LO optics, and specialized quasi-optical filters. During the early commissioning phase, the system successfully captured the dynamical evolution of a strong magnetohydrodynamic (MHD) mode in the core of an ohmically heated L-mode plasma. By providing direct 2D visualization, the system enables a comprehensive characterization of the mode structure and its temporal behavior. These initial results confirm the effectiveness of the ECEI system as a crucial diagnostic tool for investigating complex MHD instabilities in WEST.