AUTOOSCILLATIONS IN DIELECTRIC SUSPENSIONS WITH THE “NEGATIVE ” VISCOSITY EFFECT

We consider an active system, consisting of dielectric particles, under the action of electric field. Rotation of particles in liquid is synchronized by the Couetta flow. To observe oscillations, we put a plate on the liquid layer and attach it to a spring. A situation is considered when the polarization time is small in comparison with the typical mechanical relaxation time. In such case, the stationary point can be unstable and, due to the “negative ” viscosity effect, autooscillations of the plate could be observed, if the strength of an external electric field is beyond some critical value. We derive the exact range of parameters, when autooscillations of the plate are possible, and numerically calculate the period. It is also shown that beyond this range the system becomes stable and stressed, thus imitating the behaviour of the muscle cells. Introduction. Active systems have attracted much interest recently. They are responsible for the functioning of the cell, motility of different microorganisms [1]. Different unusual properties of these systems are known, for example, the muscle cells of oysters develop high tension keeping them closed by expenditure of energy. Creation of different systems (gels and other), exhibiting the propertie