Hydrodynamic instability in ohmic regimes with imperfect electric membranes

The transition to overlimiting currents directly from prelimiting regimes bypassing the limitingcurrent stage is considered for imperfect electric membranes. The hydrodynamic instability of the onedimensional equilibrium state, which is a result of the balance between diffusion and electromigration, is investigated. The influence of volume and surface effects on instability and the transition to overlimiting currents is estimated under variation of the membrane selectivity. It is found that the dominating mechanism of instability is destabilization of the residual space charge. The fact of the replacement of monotonic instability by vibratory instability with a vibration frequency of about 50?300 Hz has been discovered.