Stability Measurements of a Superconductor Cooled By a Two-Dimensional Channel of Helium II

This report presents measurements on the stability of a He II cooled superconductor. The conductor is helically wound in a phenolic coil support and is cooled by a channel of He II which allows for heat transfer in two dimensions. Stability is measured by recovery of the superconducting state following a transient burst of heat. The data also allows one to measure normal zone propagation velocities and temperature profiles at various times. Currents in the conductor range from 0 to 5 kA with background magnetic field ranging from 0 to 11 tesla. Descriptions of stability boundaries are given in terms of maximum energy bursts from which the conductor recovers as a function of transport current, channel size and background field. Comparisons of the data with an analysis of stability in a one-dimensional channel are shown to be useful. This experimental configuration is intended to model some aspects of a superconducting magnetic energy storage system.