Simulation of the Thermoelectrically Generated Magnetic Field in a SC Nine-Cell Cavity

Several studies [1-3] showed that thermocurrents generate a magnetic field in a horizontal cavity test assembly or cryomodule, which may get trapped during the superconducting phase transition. The trapped flux causes additional dissipation during operation and can therefore significantly degrade the cavity’s quality factor. We simulated the distribution of the generated magnetic field for an asymmetric temperature distribution and compared the results to experimental findings. Furthermore, the impact of a growing superconducting area on the magnetic field distribution was investigated. The simulations complement the experimental studies because direct measurements are only feasible with a limited number of magnetic field probes and hence restricted to selected locations and orientations. The simulations allow to analyze the local data in the context of the whole system. NUMERICAL SIMULATIONS