An innovative system for dry cooling of solenoid-type high-field High Temperature Superconducting (HTS) magnet is presented. A single two-stage cryocooler is the cold source and two-phase passive heat transport devices namely pulsating heat pipes (PHP), also called oscillating heat pipes, serve as the thermal links. The HTS magnet is metal-as-insulation type constructed from REBCO tapes and designed for 10 T at 250 A. Both the heat generated by the magnet and that of the current leads are supported by the cryocooler’s first and second stage cooling capacities. Two PHPs, each made with serpentine-shaped 20 parallel stainless-steel capillary tubes, are designed such it can maintain the magnet in 30 K as well as 10 K temperature range. The PHPs work with very small volume (few millilitres) of liquid cryogen confined within the PHP tubes thereby eliminating the complexities and costs associated with liquid cryogen baths. The thermal performance of this autonomous demonstrator is shown during magnet quench and charging in direct current (DC) and alternating current (AC) modes with helium as the working fluid of PHPs. Particularly, during the AC mode, this system has the ability to precisely quantify the AC loss power dissipation within the magnet.
Acknowledgement: This work is supported by the Agence National de la Recherche (ANR) through the Program d’Investissements d’Avenir (Future Investment Program) under Grant No. PACIFICS ANR-21-ESRE-0049.

Keywords
HTS magnet|Cryogenic PHP cooling|AC loss measurement|Helium|Cryocooler