Testing a Synthetic ECE Diagnostic for ITER*

Electron cyclotron emission (ECE) diagnostics for ITER will measure plasma electron temperature with high spatial and temporal resolution, and are used to detect neoclassical tearing modes (NTMs). Interpreting ECE requires anticipating physical limits including frequency cut-offs and harmonic overlap. Additionally, in high temperature plasmas relativistic shift and broadening of the emission must be considered to accurately reconstruct the electron temperature spatial profile. Accounting for these effects allows ECE diagnostics to be used for accurate measurement of the equilibrium electron temperature profile, as well as fluctuations about this equilibrium. One such fluctuation is caused by the fast radial transport of heat across magnetic islands. ECE diagnostics can detect this change as an oscillation at the plasma rotation frequency to determine the existence and location of NTMs. This poster presents work on a synthetic diagnostic for ECE. The synthetic diagnostic tests simulated ECE signals that account for anticipated physics issues are derived from simulated ITER scenarios, perturbed with magnetic islands. The diagnostic tests ECE detection of NTMs in real-time. Combined, these two areas of focus help determine design of the ECE system.