ON THE EVALUATION OF THE MAGNETOSTATIC FIELD DUE TO STATIONARY CURRENTS IN TOROIDAL SOLENOIDS

The study of the magnetostatic field due to a stationary current in a coil wound around a toroid is usually limited to the determination of the toroidal magnetic induction due to the poloidal component of the c urrent using Ampere's circuital law. This paper emphasizes that poloid al (toroidal) currents produce toroidal (poloidal) magnetic induction fields, presenting the explicit integration of Poisson's equation for the toroidal magnetic induction based on the use of the harmonic expan sion of the inverse of the source point-field point distance; the pres ence and importance of the circling field due to the azimuthal current s associated with the pitch in the coil is also discussed.