Dissipation in a Superconducting Indium Wire

Abstract

A superconducting device which has evolved into several useful forms is the persistatron.¹ Recently the persistatron has been modified into a coupled superconducting circuit in which the two branches of the device are deliberately made interacting.² This multiply connected, self-interacting superconducting circuit is referred to as a “coupled persistatron.” A current i _s in a coil of inductance L produces a field H _s at a wire centered in the coil. Thus a transport current i _w carried by the wire is influenced by i _s . The behavior of the system, that is, the apportionment of the currents i _s and i _w between the two branches, can be predicted by using only the princples that (a) a dissipation-producing flow apportionment is dynamically unstable against a lossless apportionment whenever the latter is possible for a given total current, and (b) the quantization of system energy due to flux conservation when the multiply connected system is in the superfluid state prevents any further current changes once a lossless flow pattern has been attained. Previous experimental results in this laboratory for i _s and i _w as a function of input current I = i _s + i _w agree very well with the theoretical predictions.²

This research was supported by the Research Corporation.