ビスマス系銀シース多芯テープ超電導線材の常電導伝播特性

抄録

It is expected that the normal-zone propagation of high-temperature superconductor (HTS) is slower than that of low-temperature superconductor (LTS) because of its large heat capacity. If the normal-zone propagates too slowly, hot spots will develop, possibly resulting in permanent conductor damage. Accordingly, it is necessary to measure propagation for designing of HTS magnet quantitatively. This paper describes electromagnetical and thermal behaviors during normal transition in Bi-2223/Ag superconducting multifilamentary tapes by conduction cooling. Some experiments were carried using operating temperature, 10-40K, and transport current as parameters in zero magnetic field. Sample tapes are transmitted normally with heater to initiate a quench. The voltage and temperature properties which accord with a normal transition are measured by voltage taps and thermocouples attached to sample tapes, and we also calculated longitudinal and transverse directions normal-zone propagation velocities from the voltage traces. In the case of conduction cooling, we investigate the cooling effect due to the length of the sample tape because its cooling condition is different from the case of using a coolant, for example liquid helium.