The thermal stability of various Fe- and Ni-sheathed MgB2 conductors was studied experimentally and numerically. Attention was focussed upon the estimation of the quench propagation velocities, vp, minimum quench energies and minimum propagating zones. The measurements were performed under self-field and adiabatic conditions, for various temperatures and transport currents. Energy pulses were introduced into the conductor by passing rectangular current pulses through a graphite-based epoxy heater. The measured voltage around the heater, together with numerical simulation, permitted the estimation of the minimum propagating zone. The vp was then obtained by monitoring multiple voltage taps and thermocouples along the conductor. The effect of the current sharing temperatures, IC(T), of the superconductor, and thermal and electrical properties of the metal sheath, were analyzed. The simulated results, obtained by solving the 1-dimensional heat balance equation of the system, were in qualitative agreement with experimental ones.

Quench Development and Propagation in Metal/MgB2 Conductors. E.Martínez, F.Lera, M.Martínez-López, Y.Yang, S.I.Schlachter, P.Lezza, P.Kovác: Superconductor Science and Technology, 2006, 19, 143-50