On the Relation Between the Nonlinear Surface Impedance and the Superfluid Current Density in High-Temperature Superconductors
Eduard Rocas, Juan C. Collado Gomez, James C. Booth, Alberto Padilla
The nonlinear surface impedance is related, by use of the surface impedance definition as the ratio between the electric field and magnetic field at the HTS surface, to a local description of the nonlinear superfluid current density that depends on the condensate velocity. To do that, we follow a rigorous approach based in the time-domain nonlinear London equations and the two-fluid model. The instantaneous magnetic field is solved inside the superconductor and the initial decay rate lambda is found to depend on the instantaneous volume current density at the surface. Then, the definition of the surface impedance is applied to a sinusoidal signal to obtain the nonlinear surface impedance that differs from the most used phenomenological formula, which is a direct extension of the lineal surface impedance obtained in the frequency domain. The formulation is compared with harmonic balance simulations of an equivalent circuit that models a plane wave propagating across a vacuum-HTS boundary with very good agreement
, Collado, J.
, Booth, J.
and Padilla, A.
On the Relation Between the Nonlinear Surface Impedance and the Superfluid Current Density in High-Temperature Superconductors, IEEE Transactions on Applied Superconductivity, [online], https://doi.org/10.1109/TASC.2010.2085030
(Accessed December 2, 2023)