Modeling of electromagnetic and thermal diffusion in a large pure aluminumstabilized superconductor under quench

I,off temperature composite superconductors stabilized with extra large cro ss-section pure aluminum are currently in use for the Large Helical Device in Japan, modern big Detectors such as ATLAS at CERN, and other large magne ts. In these types of magnet systems, the Fated average current density is not high and the peak field in a region of interest is about 2-4 T, Aluminu m stabilized superconductors result in high stability margins and relativel y long quench times. Appropriate quench analyses, both for longitudinal and transverse propagation, have to take into account a rather slow diffusion of current from the superconductor into the thick aluminum stabilizer. An e xact approach to modeling of the current diffusion would he based on direct ly solving the Maxwell's equations in parallel with thermal diffusion and c onduction relations. However, from a practical point of view such an approa ch should be extremely time consuming due to obvious restrictions of comput ation capacity. At the same time, there exist certain ways that simplify ma thematical models for the thermal and electromagnetic diffusion processes f or the purpose of rapidly calculating the propagation velocity and effectiv e simulating of quench behavior. These models explained here mere tested an d applied to quench simulation in the above-mentioned magnet systems.