Tuesday, April 25, 2017
Phase contrast imaging (PCI) is an interferometric technique commonly used to measure line integrated density fluctuations in tokamak plasmas. The tangential configuration of the PCI at the TCV tokamak in Switzerland is optimized to localize measurements through the use of a spatial filter. However, microturbulence studies in advanced scenarios with large, sheared flows suffer from the presence of Doppler shifts that are picked up along the field-tangential integration path. In this talk we show that such difficulty can be partly overcome and used to great advantage by using a new analysis method that combines data from PCI, Charge Exchange Recombination Spectroscopy and Thomson Scattering diagnostics to provide improved localization. This technique has been successfully tested and is expected to provide intriguing data on a previously observed inversion of turbulence propagation across L-H transitions in an upcoming TCV experimental campaign.