Experimental investigations of turbulent structure propagation across a -velocity shear

Abstract The influence of an externally generated E × B shear flow on the propagation of structures in drift-wave turbulence is investigated in a linear laboratory plasma device. Spatiotemporal studies of the dynamics of turbulent structures reveal that structures have a radial component of propagation, thereby contributing mainly to the fluctuation induced particle flux and leading to intermittent density fluctuations in the edge plasma. A radially localized radial E × B -velocity shear layer is generated by a biased emissive filament. The shear layer modifies the phase between density and potential fluctuations, which results in a reduction of transport driven by electrostatic turbulence. A shear decorrelation of the structures, i.e. a decrease of their radial correlation length, is not observed.