Vortex dynamics and losses due to pinning: Dissipation from trapped magnetic flux in resonant superconducting radio-frequency cavities

Abstract

We use a model of vortex dynamics and collective weak pinning theory to study the residual dissipation due to trapped magnetic flux in a dirty superconductor. Using simple estimates, approximate analytical calculations, and numerical simulations, we make predictions and comparisons with experiments performed in CERN and Cornell on resonant superconducting radio-frequency NbCu, doped-Nb and Nb${}_3$Sn cavities. We invoke hysteretic losses originating in a rugged pinning potential landscape to explain the linear behavior of the sensitivity of the residual resistance to trapped magnetic flux as a function of the amplitude of the radio-frequency field. Our calculations also predict and describe the crossover from hysteretic-dominated to viscous-dominated regimes of dissipation. We propose simple formulas describing power losses and crossover behavior, which can be used to guide the tuning of material parameters to optimize cavity performance.

arXiv comment15 pages, 8 figures

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Cited by in corpus (16)

• Role of surface defects and material inhomogeneities for vortex nucleation in superconductors within time-dependent Ginzburg-Landau theory in 2 and 3 dimensions
• Flux expulsion in niobium superconducting radio-frequency cavities of different purity and essential contributions to the flux sensitivity
• Superheating fields of semi-infinite superconductors and layered superconductors in the diffusive limit: structural optimization based on the microscopic theory
• Analysis of Magnetic Vortex Dissipation in Sn-Segregated Boundaries in Nb${}_3$Sn Superconducting RF Cavities
• Tuning microwave losses in superconducting resonators
• Two different origins of the Q-slope problem in superconducting niobium film cavities for a heavy ion accelerator at CERN
• Nonlinear Dynamics and Dissipation of a Curvilinear Vortex Driven by a Strong Time-Dependent Meissner Current
• Effect of random pinning on nonlinear dynamics and dissipation of a vortex driven by a strong microwave current
• Impact of geometry on the magnetic flux trapping of superconducting accelerating cavities
• Simple model for the RF field amplitude dependence of the trapped flux sensitivity in superconducting RF cavities
• Vortex Dynamics and Dissipation Under High-amplitude Microwave Drive
• Microwave Microscope Studies of Trapped Vortex Dynamics in Superconductors
• Measurements of the amplitude-dependent microwave surface resistance of an Au/Nb bilayer
• Ac losses in field-cooled type I superconducting cavities
• DC-driven separation of fractional flux quanta in two-band superconductors
• Dissipation by surface states in superconducting RF cavities