Features of the formation of an electric field in a non-uniform conducting medium

Abstract

The paper considers the influence of the electric field of the current on the behaviour of a gas bubble in an electrically conductive melt. We propose a model which makes it possible to predict a change in the size of gas bubbles in a metal, provided that its crystallization occurs in the presence of an electric current. The model takes into account the interaction of the charge induced on the surface of the gas bubble — metal-gas interface — with the electric field of the current. The force that deforms the gas bubble is introduced. The magnitude of the force is determined by the charges induced on the surface of the bubble due to the action of the electric field of the current. The surface density of the charges is proportional to the square of the current density and depends on the geometry of the object that is affected, as well as on the material parameters of the medium, such as electrical resistivity and magnetic permeability. Additional forces of electrical nature acting on the surface of the gas bubble contribute to its deformation in the electric field of the current. In the presence of such forces, the interfaces between the media — liquid metal and gaseous — can be deformed. Under the conditions of an orderly motion of free electrons and their collisions with ions of the crystal lattice, the size of the interfaces between the media can be changed. The gas bubble under the action of additional forces is deformed and can subsequently be fragmented.