PLASMA VORTICES AND THEIR RELATION TO CROSS-FIELD DIFFUSION - A LABORATORY STUDY

Low-frequency, flute-type electrostatic fluctuations propagating across a strong homogeneous magnetic field are studied experimentally. The fluctuations are generated by the Kelvin-Helmholtz instability. The presence of relatively long-lived vortexlike structures in a background of wideband turbulent fluctuations is demonstrated by a conditional sampling technique. It is demonstrated that in spite of the large-scale convection patterns associated with these structures, they can in some cases contribute only modestly to the turbulent plasma flux across the magnetic-field lines. © 1990 The American Physical Society.