Abstract by Jared Carlson
Physics and Astronomy
Role of grain boundaries on magnetic vortex nucleation in RF superconducting cavities
Superconducting Radio Frequency (SRF) cavities are important components of particle accelerators. SRF cavity performance is limited by a maximum allowed applied magnetic field, known as the superheating field (Hsh) at which magnetic vortices spontaneously enter the material and cause the superconducting material to quench. Previous work has calculated the theoretical maximum field a superconductor can withstand. However, this calculation assumed a perfectly smooth surface with no material inhomogeneities or surface roughness, whereas real world cavities exhibit these characteristics. I use the time-dependent Ginzburg-Landau theory to model the role of surface defects and material variation in magnetic vortex nucleation. Results show that the amount by which Hsh is reduced depends on the concentration of impurities as well as the physical dimensions of the defect. Reducing the size of grain boundaries and material inhomogeneities found therein has the potential to significantly increase SRF cavity performance.