Space-charge influence on non-linear beam defocusing.

Some of the investigations in the past few years have shown that organic liquid dielectric, containing space charge have structuralized regions. The report contains results of experimental investigation of nonlinear optoelectrohydrodynamics (OEGD) effect, which appears under the transmission of a helium-neon laser beam through low-conducting liquids as a result the light absorption and heating of translucent liquid leads to spontaneous defocusing of laser beam, a laser power exceeding 1 mVt. Effect is non-excited liquid is isotropic. Effect has threshold tension being 1 kV/sm. Under the effect of the electric field of 1 kV/sm. on liquid, defocusing is decreasing, space anisotropism arises due to the space electric charge and electrohydrodynamic currents. This influence of electrohydrodynamic (EHD) currents is very significant and is brought about by connective heat conduction. The separate hydrodynamic and charge effects specific experiments were carried out in the system of partially isolated electrodes. Anisotropism of OEGD-effects has been established under these conduction. It has been shown that liquid acquires anisotropic properties due to structured molecules in the ionic field, forming space charge. Anisotropic properties of low-conducting liquids, in the absence of EHD-currents are being preserved during several hours after voltage is off.