Koyo Tamura

Anomalous diffusion and Lévy distribution of particle velocity in soft-mode turbulence in electroconvection

We study the complex behavior in soft-mode turbulence (SMT), a recently discovered type of spatiotemporal chaos observed in electrohydrodynamic instability (EHD) of a nematic liquid crystal with homeotropic alignment. A particle, small compared to the characteristic length of the macroscopic flow, injected in SMT travels with random velocity such as an active Brownian motion. Tracking the particle trajectory induces changes in the flow velocity as a function of space and time (the Lagrange picture). The mean amplitude of the velocity is linearly proportional to the control parameter e, normalized voltage in EHD. The probability density distribution of the particle velocity changes from Levy for small e to Gaussian distribution for large e through intermediate distributions. The different regimes of anomalous diffusions are also observed. The stochastic properties of SMT are discussed based on these results.

Nonlinear Transport and Anomalous Brownian Motion in Soft-Mode Turbulence

Soft-mode turbulence (SMT) is a recently discovered type of spatiotemporal chaos observed in the electrohydrodynamic instability (EHD) of a nematic liquid crystal with homeotropic alignment. Its novelty is that it occurs as therst supercritical bifurcation from a stable stationary state in the weakly nonlinear regime of EHD. A particle, small compared to the characteristic length of the macroscopicow, injected in SMT travels with random velocity similar to a particle in Brownian motion. Wend that the particle trajectory exhibits anomalous Brownian motion such as pumpedight and that the macroscopic diusion constant due to weak turbulence is about 10 3 times larger than the diusion constant associated with the rest state. The stochastic properties of SMT are discussed.

Control parameter dependence of spatial domain structures in soft-mode turbulence

Soft-mode turbulence (SMT) is a spatiotemporal chaos in electrohydrodynamic convective systems. It is caused by a nonlinear interaction between the convection mode and a Nambu–Goldstone mode, and b...