Chaos in Coulomb driven EHD flows

We deal here with chaotic charge trapping in finite amplitude electroconvec tion. In steady finite amplitude electroconvection ions can not enter the r egion where the downward vertical velocity is larger than the upward ionic velocity. Consequently there is an inner region in the convection cell that remains free of charge. When the liquid velocity is time dependent, as it is always observed in experiments, this region is no longer free of charge. Lobe dynamics analysis is used to elucidate the mechanism of charge trappi ng.