Single Turn Domain in 3D

Have anyone used the "Single Turn Domain" in 3D?
I'm doing something research about eddy current and the influence of the environment(change of temperature) in 50kHz in a conductor in a magnetic field, which is produced by coils. for the coils i used the "single turn domain" and "Gap feed" to model them and find that it's very hard to get a convergent result in the study "frequency-stationary".

and then in the User's Guidebook, chapter："Using Coils in 3D Models", i have found that:

"The Gap Feed should be used with care in high frequency modeling as there is a mesh dependent displacement current density flowing in the elements just outside the bounding edges of the Gap Feed boundary. "

so i want to know if the Influence of this "displacement current density" is very big on the magnetic field or not. How can i reduce this Influence? feiner Mesh or coarse Mesh nearby the coils is needed? Except the mesh have the electrical conductivity of the coils also influence on this "displacement current density"?

thanks for all answers