Analysis of the Quench Onset and Propagation in ${\rm MgB}_{2}$ Conductors

We present the numerical and experimental analysis of quench development and propagation of Cu-stabilized MgB₂ conductors. Energy pulses were deposited locally to the conductor, and the temperature and the electric field profiles around this point heat disturbance that gives rise to a quench, as well as their time evolution, were measured. Numerical results obtained by solving the one-dimensional heat balance equation of the system have been used to analyze the effect of the finite n-value of the power-law V(I) curve of the superconductor, on the parameters characterizing the quench: minimum quench energy (MQE) and the temperature and the size of the minimum propagating zone (MPZ). The experimental results are in qualitative agreement with the simulated ones. Moreover, MQE´s of Cu-stabilized and non-stabilized conductors have been compared. Our results show that the Cu-stabilization of MgB₂ wires leads to enhanced thermal stability with a higher minimum quench energy (MQE) hence significantly reduces the possibility of local burnout as seen in standard Fe-sheathed wires.