Family of Lamé spheroconal quadrupole harmonic current distributions on spherical surfaces as sources of magnetic induction fields with constant gradients inside and vanishing asymptotically outside

Constant gradient magnetic induction fields play key roles in Magnetic Resonance Imaging and in Neutral Atom Traps. This communication reports the construction of a family of solutions of the magnetostatic Gauss and Ampere laws in their boundary condition forms, identifying the Lamé quadrupole spheroconal harmonic current distributions on spherical surfaces as sources of magnetostatic fields with constant gradients inside and vanishing asymptotically outside. The advantages of the spheroconal quadrupole sources and fields, which include the familiar spherical harmonic counterparts as special cases, are illustrated analytically and graphically.