Speaker
Danilo Liarte
(Cornell University)
Description
In this talk, I will explain the hysteretic mechanisms that are responsible for field-dependent residual losses of SRF cavities due to the motion of isolated trapped vortex lines under the action of parallel oscillating fields at the surface. By invoking collective weak pinning theory in the context of the Bardeen-Stephen model of vortex dynamics, I will present simple estimates, approximate analytical calculations, and numerical simulations that compare well with cavity tests performed in CERN and Cornell. Our simple formulas describing power losses and crossover behavior can be used to guide the tuning of material parameters to optimize cavity performance.
