Electric field in solenoids

Abstract

The time-varying electric field inside a solenoidal coil is measured using a new sensor that minimizes the field disturbance. The experimental results clearly indicate that the main field inside a solenoidal coil is not in the azimuthal direction, but in the axial direction. It is shown that this axial field is generated by surface charges, which are formed to cancel the inductive field inside a conducting wire.