Violation of parity in nonlinear saturated state of drift vortices

Summary form only given, as follows. The nonlinear saturated state of the Kelvin-Helmholtz (K-H) instability have been investigated experimentally in detail. The adjustable radial electric field profile responsible for the inhomogeneous ExB flow profile was controlled by electrodes at the plasma-column ends. In the experiments, stationary turbulence was generated in a rotating system with nonlinear energy transfer over scales from the pumping region (azimuthal wave number m∼10) to the dissipative region (m∼1), so that the regions of energy source and sink were very well separated. In our experiments it was found that the observed amplitudes were strongly different for odd and even azimuthal modes in the nonlinear saturated state. It was shown that this violation of parity was determined by the sign of the dominant mode. When the dominant mode m=1 was present, all the observed odd modes (m=1, 3, 5, 7, ...) had amplitudes order of magnitude higher than their the even neighboring mates. Similar effects were observed when m=2 mode was dominant, then the prevalence of even modes was clearly present. Thus, the nonlinear interaction of modes with each other are determined by the parity of the predominant mode and vortices of like polarity have the largest amplitudes.