Experimentum Crucis for Magnetic Interaction
Stewart Ian Wells
The investigation of the long-standing controversy over the precise formulation of the magnetic interaction between steady currents (or between uniformly moving charges) is re-opened. An experimental technique is proposed whereby the distinction between the Ampere-Weber ?central force' formulation and the Grassmann-Lorentz ?normal force' formulation can be demonstrated decisively within a modestly equipped laboratory. Although no preference is advanced on theoretical grounds, a confirmation of the ?normal force' law would have notable consequences for theory: the third law of motion could only be satisfied through reaction against a background medium, and the possibility of a ?jetless' propulsion system is thereby suggested. It is also argued that the ?longitudinal' portion of the original Ampere force law is nonetheless compatible with, and perhaps necessary for, either possible outcome.
