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

Abstract

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.