Experimental study of the dynamics of conditionally averaged structures in weakly developed electrostatic turbulence

An experimental study of coherent structures in the electrostatic turbulence observed in a steady-state operated, magnetized, cylindrical low-beta argon plasma is presented. The conditional averaging technique is used to detect and to characterize large-scale conditional structures. The results of conditional averaging of a single drift wave mode are consistent with theoretical predictions and the data obtained by an azimuthal array of 64 Langmuir probes. In the turbulent regime, large monopole structures in the density fluctuations are identified, which develop by particle trapping due to associated potential structures. These structures lead to transport of particles across magnetic field lines, as evident from the trajectory of the structures. The comparison of the dynamics of conditional structures and unaveraged spatiotemporal structures suggests that they are of the same origin. (C) 1999 American Institute of Physics. [S1070-664X(99)02403-9].