Optical electrostriction pressure in liquid, solids and gases

The electrostriction pressure is accompanied by the compression of the body located in an electrical field. As a result, a part of the energy of the electrical field is transferred into the elastic energy connected with the compression of the body. There is a minimum of the total energy at a steady state. We calculate the minimum and determine a magnitude of the compression and the pressure responsible for the compression. The pressure is equal to the electrostriction pressure. It turn out that the well-known expression for the electrostriction pressure is valid for liquid and solids on assumption that a change of their volumes is negligible small. This expression is not valid for gases. There is a threshold, below which the electrostriction pressure is absent. The threshold for the atmosphere air at normal conditions is about 7.4 107 J/m3.