Title :
Stability of superconducting wire with various surface conditions in pressurized He II (1)-experimental results
Author :
Ohya, M. ; Shigemasu, S. ; Shirai, Y. ; Shiotsu, M. ; Imagawa, S.
Author_Institution :
Dept. of Energy Sci. & Technol., Kyoto Univ., Uji, Japan
fDate :
6/1/2005 12:00:00 AM
Abstract :
Stability tests were performed for two small test coils wound with NbTi/Cu composite superconducting wires with different surface conditions respectively. One is a 0.5 mm-diameter bare wire with the copper ratio of 1.3. Another is the same wire with chemically oxidized copper surface. The stable limit current under constant magnetic field greatly increased by shifting to He II cooling from He I cooling for both wires, but stationary normal zones were observed in wide current area lower than the stable limit currents for the oxidized wire. The characteristic of the stability of a superconducting wire is more deeply dependent on the conductor surface condition cooled by He II than that in case of He I cooling.
Keywords :
composite materials; copper; critical current density (superconductivity); helium; mechanical stability; niobium alloys; quenching (thermal); superconducting coils; thermal conductivity; titanium alloys; 0.5 mm; He; He I cooling; He II cooling; Kapitza conductance; NbTi-Cu; NbTi-Cu composite superconducting wire; chemically oxidized copper surface; constant magnetic field; cryogenic stability; experimental results; limit current; pressurized He II; superconducting coil; superconducting wire stability; superfluid helium; surface condition; Cooling; Copper; Helium; Niobium compounds; Performance evaluation; Stability; Superconducting coils; Superconducting filaments and wires; Testing; Wounds; Cryogenic stability; Kapitza conductance; superconducting coils; superfluid helium;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
DOI :
10.1109/TASC.2005.849261
