An improved TDE technique for derivation of 2D turbulence structures based on GPI data in toroidal plasma

This paper reports an improved time-delay estimation (TDE) technique for the derivation of turbulence structures based on gas-puff imaging data. The improved TDE technique, integrating an inverse timing search and hierarchical strategy, offers superior accuracy in calculating turbulent velocity field maps and analyzing blob dynamics, which has the power to obtain the radial profiles of equilibrium poloidal velocity, blob size and its radial velocity, even the fluctuation analysis, such as geodesic acoustic modes and quasi-coherent mode, etc. This improved technique could provide important 2D information for the study of edge turbulence and blob dynamics, advancing the understanding of edge turbulence physics in fusion plasmas.