Analytical Model of Thermoelectrical Behavior in Superconducting Resistive Core Cables

High field superconducting Nb3Sn accelerators magnets above 14T, for future High Energy Physic applications, call for improvements in the design of the protection system against resistive transitions. The longitudinal quench propagation velocity (vq) is one of the parameters defining the requirements of the protection. Up to now vq has been always considered as a physical parameter defined by the operating conditions (the bath temperature, cooling conditions, the magnetic field and the over all current density) and the type of superconductor and stabilizer used. Keeping the total amount of stabilizer constant and segregating a percent into the core and tuning the contact resistance between the superconducting strands and the core, it is possible to enhance the quench propagation velocity. Computer simulations and analytical model are presented to explain the phenomenon. The consequences with respect to minimum quench energy are evidences and the strategy to optimize its designed is discussed.