Measurement and scaling of the radial correlation lengths of turbulence atthe plasma edge of ASDEX Upgrade

With the single-frequency swept reflectometry diagnostic on ASDEX Upgrade r adial correlation lengths of the plasma turbulence can be determined by a n ew quasi-simultaneous correlation technique. The scaling of the observed mi croturbulence is investigated in detail through the correlation lengths mea sured 2 cm inside the separatrix. During the low-temperature L-mode and nea r the LH transition these scale according to the resistive ballooning turbu lence model. For L- and H-mode plasmas with higher temperatures the correla tion lengths scale with the effective Larmor radius as expected for dominan tly eta(i) driven turbulence.