Philosophy of a quench; two case studies - LTS wiggler magnet and HTS mu-SMES

The utilisation of HTS composites raises the obvious question of how the st ability of these materials differs from that of classical ones. The improve d stability of HTS is due to the increased specific heat and a wider temper ature margin between the operating and critical temperature. The quench ana lysis of HTS magnet system is however quite different from their LTS counte rparts because of the slanted E(J) characteristic due to the thermally acti vated flux creep and macroscopic material inhomogeneities. The comparison o f different quench parameters of a 6 T LTS wiggler and a 5 kJ HTS SMES have been evaluated. The former system is installed in a 1.5 GeV electron stora ge ring in the University of Lund, Sweden, and the latter has been demonstr ated to compensate a short term loss of power. The stability considerations are projected to the essential quenching factors, for example normal zone propagation (NZP), hot spot temperature, current decay and internal voltage .