Dependence of the superconducting superheating field on material inhomogeneity

In particle accelerators, Superconducting Radio Frequency (SRF) cavities are used to transfer energy to particles through induced electric fields. A limiting factor in the efficiency of these cavities is the superconducting material’s properties, mainly the so-called superheating field, i.e., the largest magnetic field that the superconductor can withstand before becoming a normal metal. Using the Ginzburg-Landau model, we explore the dependence of the superheating field on the type and purity of the superconducting materials used. We solve the Ginzburg-Landau equations using finite element numerical methods.  Our goal is to understand the role of material inhomogeneity, such as those found at grain boundaries, in determining a sample's superheating field.  Our results will allow for more effective SRF cavities to be constructed, which will decrease both the cost and size of particle accelerators.