Correlation ECE Diagnostic
Correlation radiometers measure the electron temperature fluctuations that are contained within the electron cyclotron emission (ECE) spectrum. The fluctuations in the ECE radiation intensity are dominated by uncorrelated thermal noise, and plasma electron temperature fluctuations are recovered by isolating the correlated signal between two or more ECE measurements. This system operates as a poloidal correlation radiometer through spatial decorrelation of the electron cyclotron emission with disjoint measurement volumes. The 32 channels are distributed through 4 separate volumes. Two volumes are located above and below the plasma mid-plane on the high-field side (HFS) of the magnetic-axis, while the other two measurements are located along the plasma mid-plane on the low-field side (LFS) of the magnetic-axis. The LFS diagnostics cross similar plasma volumes between 70%-90% of the plasma minor radius.