Effect of the thermal barrier on the stability of cable-in-conduit conductors

As the enhancement of stability margin of cable-in-conduit conductors, the effect of thermal barrier provided inside the surface of strand has been investigated. Firstly, by a simple model calculation, it is shown that the energy needed to raise the temperature of a strand as the simulation of the disturbance due to surface friction, depends strongly on the pulse duration and thermal conductivity of surface material. Next, as based on this consideration, strands with the thermal barrier inside its surface have been made and the stability test has been carried out. From the result, it was shown that the stability margin of a cable-in-conduit conductor consisting of strands with the thermal barrier can be calculated with the enthalpy of whole helium whithin the conduit even near the critical current.