Generation of bubbles in liquid argon and nitrogen in divergent electric fields

In this paper, we present an experimental study of high field conduction phenomena in liquid argon and liquid nitrogen in a point-plane electrode geometry. These liquids behave qualitatively like saturated hydrocarbons except when they are studied close to their normal boiling point. The generation and dynamics of microscopic bubbles as a function of various parameters (nature of the liquid, injected energy and hydrostatic pressure) are presented and discussed. The possible influence of these phenomena on electrical insulation at cryogenic temperatures is also discussed.