An Exponential Law of Hot Spot Temperature Versus Normal Zone Propagation Velocity During the Quench of an NYBa2Cu3O7-δ Pancake Magnet

Using a 2-D/3-D mixed electrothermal model, the quench behavior of an YBa2Cu3O7-delta (YBCO) pancake magnet is investigated for operating temperature 30-65 K. From many simulations, it is found when the hot spot temperature T-peak rises to the range [120 K, 300 K], both T-peak and the normal zone length L-NZ behave like exponential functions of the longitudinal normal zone propagation velocity (NZPV), as the YBCO pancake magnet is quenched by a disturbance energy (DE) equal to or greater than the minimum quench energy (MQE). The exponential law of T-peak versus NZPV, as well as L-NZ versus NZPV, is not obviously affected by the heat disturbance parameters as DEs = MQEs. Similarly, the temperature rising rate dT(peak)/dt can be regarded as a function of T-peak in [120 K, 300 K] and is not significantly affected by heat disturbance parameters as DEs = MQEs. These characteristics have potential usage in the formulation of quench detection/protection schemes of HTS YBCO pancake magnets.

Automated summary

The study reveals that the hot spot temperature, normal zone length, and temperature rising rate exhibit exponential functions in a specific range, with minimal influence from different heat disturbance parameters. These findings suggest potential applications in quench detection and protection schemes for HTS YBCO pancake magnets.