Bubble dynamics and transition into streamers in liquid dielectrics under a high divergent electric field

The paper deals with the dynamics of a bubble initiated in the vicinity of a sharp electrode in a liquid dielectric gap submitted to an electric field , and to the conditions leading to the generation of a streamer at the bubb le-liquid interface. By taking into account the different stresses acting a t any point of the surface of the bubble, we establish a mathematical expre ssion describing the shape of the bubble and allowing us to analyse its def ormation and instability. The frequency of the disturbances at the interfac e is studied and the zone at which the local electric field is the highest is determined. It is shown that depending on this frequency and therefore o n the value of the local electric field, different streamer patterns can be generated. Some examples of the topology of the disturbed interface are gi ven and discussed.