Minimum quench energy studies on Bi-2223/Ag tape operating at nitrogen atmosphere

Minimum quench energy (MQE) and the effect of quench energy on quench propagation velocity of Bi-2223/Ag superconducting tapes are studied in this paper. The experiments were carried out with zero background magnetic field under the cooling condition of nitrogen atmosphere. By measuring quench behavior of sample tape near heater, MQE can be obtained quickly. The experiments show that once quench propagates, propagation velocity has nothing to do with quench energy. Furthermore, MQE is relevant to a width of heating wire. Only when the energy pulse of heater is large enough to make the triggered region reach minimum propagation zone, quench propagation can be initiated. In addition, we have also derived the transport current dependence of MQE in Bi-2223/Ag superconducting multifilament tape.