Correlation Reflectometry

Poloidal correlation reflectometry is a microwave diagnostic that utilizes an array of microwave antennae to probe plasma density fluctuations at different positions on the flux surface. From the phase delay between the individual measurements the velocity and correlation length of the fluctuations can be derived. In addition the radial electric field and the magnetic pitch angle can be estimated from the measurements. The radial localization depends on the plasma density profile (O-mode polarization). Radial resolution is achieved by chang ing the microwave frequency (Ka - Band 24 - 40 GHz). In OP1.2 the system will be upgraded to measure simultaneously at two different frequencies corresponding to two radial positions. This allows to characterize the radial correlation length.