Quench characteristics in HTSC devices

Quench dynamics in a YBCO HTSC film and a Bi-based small HTSC coil have bee n studied, While the stability margin of HTSC against a local disturbance w as very large, quench current was limited by a catastrophic temperature ris e originated from the nonlinear characteristic of Joule heating in HTSC, Th e crucial parameter for the quench becomes the nonlinear resistance in HTSC as a function of temperature and transport current. It has been shown that the dynamic characteristics of the quench in both the film and the coil ca n be described quantitatively by the simplified one-dimensional heat balanc e equation even though the time scales are different by more that six order s, i.e., several hundreds micro seconds for the film and several hundreds s econds for the tape coil.