Description of elliptic magnetic field in unshielded bifilar transmission line

Eddy currents within the neighbouring parallel conductor changes the distribution of the magnetic field within the conductor and its vicinity. The size of these changes depends on so the conductivity of the conductor and its diameter, current frequency in the phase conductor and the respective geometric configuration between this conductor and the shield or a second neighbouring conductor. Work has shown elliptic magnetic fields occurring in unshielded bifilar transmission lines in case of the internal and external proximity effect. To characterise complex vector values for such a field it is proposed to use the length of the longer ellipse semi axis which is marked by the end of the vector during one phase.