A dual gas puff imaging (GPI) system has been successfully assembled on the Experimental Advanced Superconducting Tokamak (EAST) and applied for the study of the dithering L-H transition in the 2012 spring campaign. A new method i.e., the dynamic programming based time-delay estimation technique, has been applied to the 64 × 64 pixels GPI video images to yield time-dependent two-dimensional velocity fields at the plasma edge on EAST. Local poloidal flow velocities up to ∼−3 km s −1 (in the electron diamagnetic direction) and radial flow velocities up to ∼−2 km s −1 (inward) are found inside the separatrix during a dithering burst. The radial and poloidal cross-correlation length, flow velocity and auto-correlation time inside the separatrix increase preceding the dithering burst and decrease following the dithering burst. These observations provide strong evidence for the shear flows playing an important role during the dithering L-H transition.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.