Influence of Electric Fields on the Heat Conductivity of Liquids Investigated by the Thermal Lensing Effect

Abstract

AbstractThe energy absorbed in a liquid sample from a laser beam causes an inhomogenity in the temperature and in the refractive index. This makes the sample to behave as a concave lens. In an electric field this effect, which is known as the thermal lensing effect, is reduced. For various compounds (Benzene, Toluene, Trifluorotoluene, o‐Dichloro‐benzene, Nitrobenzene) the time dependence of the intensity at the centre of the laser beam is investigated as function of the applied field. The experiments are analysed assuming an anisotropic contribution to the heat conductivity tensor, determined by the electric field. The averaged heat conductivity is found to depend linearly on the voltage, which suggests to explain the enhancement of the heat transfer from the laser beam by a micro convection connected to the small ionic current.