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TY - CONF AU - Walive Pathiranage, M.R.P. AU - Gurevich, A.V. ED - Michel, Peter ED - Arnold, André ED - Schaa, Volker RW TI - Nonlinear Dynamics and Dissipation of Vortex Lines Driven by Strong RF Fields J2 - Proc. of SRF2019, Dresden, Germany, 30 June-05 July 2019 CY - Dresden, Germany T2 - International Conference on RF Superconductivity T3 - 19 LA - english AB - Trapped vortices can contribute significantly to a residual surface resistance of superconducting radio frequency (SRF) cavities but the nonlinear dynamics of flexible vortex lines driven by strong rf currents has not been well understood. Here we report extensive numerical simulations of large-amplitude oscillations of a trapped vortex line under the strong rf magnetic field. The rf power dissipated by an oscillating vortex segment driven by the rf Meissner currents was calculated by taking into account the nonlinear vortex line tension, vortex mass and a nonlinear Larkin-Ovchinnikov and overheating viscous drag force. We calculated the field dependence of the surface resistance Rs and showed that at low frequencies Rs(H) increases with H but as the frequency increases, Rs(H) becomes a non-monotonic function of H which decreases with H at higher fields. These results suggest that trapped vortices can contribute to the extended Q(H) rise observed on the SRF cavities. PB - JACoW Publishing CP - Geneva, Switzerland SP - 560 EP - 564 KW - cavity KW - ECR KW - radio-frequency KW - niobium KW - electron DA - 2019/08 PY - 2019 SN - "" SN - 978-3-95450-211-0 DO - doi:10.18429/JACoW-SRF2019-TUP055 UR - http://jacow.org/srf2019/papers/tup055.pdf ER -