Electron Cyclotron Emission Imaging (ECEI) System for the J-TEXT Tokamak

A dual array Electron Cyclotron Emission Imaging (ECEI) system is being developed for the J-TEXT tokamak in Wuhan, China. Each 16-element array (expandable to 20 element) provides 2-D 16x8 time-resolved images of T_e profiles and fluctuations over extended regions of the J-TEXT plasma. Unique to the J-TEXT ECEI system is an electronics architecture that takes full advantage of the capabilities of PXI multifunction I/O modules which not only provide simultaneous 16-bit 2 MS/s sampling of the ECEI data, but also provide digital I/O signals that are used to remotely control individual RF channel attenuations. These are coupled with Arduino-based controllers which provide remote control of RF channel spacings (selectable between 0.8, 1.0 and 1.3 GHz) and video bandwidths. Details of this ECEI system are presented.