Essential properties of sub-cooled water ice and background field properties of MgB2 coil measured in it

Abstract

Highly sub-cooled water ice, with temperatures as low as 10–20 K is not commonly utilized and, as a result, its fundamental properties remain generally unknown. Therefore, the thermal characteristics of water ice have been thoroughly reviewed in the scientific literature and compared with the performance of other solid materials, which can be potentially used as a cooling media in superconducting applications. The effectiveness of water ice as a cooling agent was demonstrated through experimental measurements of the temperature and the magnetic background field effects on the critical current of small MgB₂ solenoid immersed in water ice with temperatures ranging from 10 K to 36 K and external magnetic fields from 0 to 6 T. Increase of the solenoid’s temperature was observed when the transport current exceeded the critical threshold, which is determined by the conventional criterion of 1 µV/cm. The obtained results confirm that sub-cooled water ice is a promising, cost-effective, and safe coolant suitable for superconducting systems.