Fundamental study for breakdown characteristic of slush nitrogen as a coolant in superconducting coil

Liquid nitrogen is mainly used as a coolant of superconducting coils. If the coolant has a higher cooling performance, it will improve the stability of superconducting coils. The authors focused on a new coolant called slush nitrogen. This is a mixed fluid containing liquid nitrogen and solid nitrogen particles. It has been reported that slush nitrogen has an excellent cooling and transporting property compared to the liquid nitrogen because solid nitrogen has a higher latent heat of melting. However, the insulation performance of slush nitrogen has not been clarified. In this study, the breakdown characteristics of slush nitrogen were investigated.