Prebreakdown and Breakdown in Liquid Nitrogen under Pulsed Heating for Superconducting Applications
Prebreakdown and Breakdown
in Liquid Nitrogen under Pulsed Heating for Superconducting Applications
An experimental study of breakdown and pre-breakdown phenomena in liquid nitrogen (LN2) is performed in this paper, in order to provide useful knowledge for the design of high voltage superconducting systems. A metallic tape subjected to pulsed heating is used as electrode, in order to properly simulate the operating conditions of a quenching superconducting apparatus. Measurements of breakdown voltages between the tape and a plane electrode tied to high voltage show the strong influence of tape polarity, LN2 temperature, and delay between heating and voltage application. Various measurements obtained with either a high-speed camera or an intensified camera allow to characterize the sequence of pre-breakdown events (i.e. liquid boiling, vapor bubble development, and streamer propagation) leading to breakdown.
R. Chassagnoux, O. Lesaint, N. Bonifaci, O. Gallot-Lavallée, P. Legendre, C. Creusot, A. Girodet