Kerr electro-optic field mapping measurements in high voltage stressed liquid and gaseous sulfur hexafluoride

Abstract

When stressed by high electric fields, liquid and gaseous SF6 become detectably birefringent. Liquid SF6 at ∼350 psi and room temperature has a Kerr constant on the order of 10−15 m/V2 for light at the free space wavelength of 633nm, which is comparable to values reported for transformer oil, polyethylene, and PMMA. The Kerr constant of gaseous SF6 is measured to strongly decrease with density. Electric field measurements between coaxial cylindrical electrodes are described where the inner cylinder is entirely supported by a half round cylinder of PMMA. The aim of these measurements is to describe surface charge accumulation at a solid/gas interface and its effect on surface discharges.