Flux Jumps in Nb-Ti Rods

Abstract

Experiments are carried out to search a behavior of a flux jump under a control over the heat leakage from Nb-Ti rods surrounded by low pressure herium gas, and the following quantities are measured: the relation between the flux-jump field and the sweeping rate, the behavior of temperatre rise and temperature fluctuations. In order to compare with the experimental results, approximate solutions of a simplified heat equation to describe a flux jump and the induced mean power losses are derived for a cylindrical specimen in which the temperature is assumed to be constant spatially. Calculations are carried out for the several quantities concerned to flux jumps. In addition, an analysis of temperature fluctuations is worked under the condition of a least heat leakage, and the criteria of flux jumps are discussed.