Confinement of longitudinal, axially symmetric, magnetic fields to annular regions with permanent magnets

摘要

A magnetic device of permanent magnet materials for the control of linearly extending annular cross-sectioned magnetic fields formed of two concentrically nesting magnetic tubular elements defining an annular space therebetween, and inner and outer cladding magnets radially disposed around the outer of said tubular elements and interiorly of the inner of said tubular elements, the cladding magnets being thicker at the end extremities and diminishing in thickness towards and to the plane of zero magnetic potential at or near the center line of the device measured along its longitudinal axis.