The Nature of Magnetism: A Physical Exploration of the Electric Origin of Magnetism

The Nature of Magnetism: A Physical Exploration of the Electric Origin of Magnetism explores a deceptively simple question: what, physically, do we mean when we say that a magnetic field is there? Modern relativistic electrodynamics unifies electricity and magnetism as different aspects of one electromagnetic field. Yet this unification leaves open a deeper ontological question: what physical reality lies behind the magnetic field we use to describe electromagnetic phenomena? The essay examines this question through familiar phenomena including the force between current-carrying conductors, the relativistic origin of magnetism, the electrical neutrality of moving currents, electromagnetic induction, self-induction, the Aharonov–Bohm effect and electromagnetic radiation. Particular attention is given to the distinction between the physical effects attributed to magnetism and the mathematical field used to represent them. Taking established Maxwell–Lorentz electrodynamics and relativistic reasoning as its starting point, the essay does not propose a new mathematical formalism. Instead, it asks whether the conventional interpretation of the magnetic field provides the most direct physical picture of what is actually present in space. Written for a broad readership interested in physics and its conceptual foundations, the essay combines historical development, familiar physical examples and relativistic reasoning to explore the relationship between electric fields, moving charges, induction, electromagnetic phenomena and the ontology of physical fields. Keywords: magnetism; magnetic field; electric field; relativistic electrodynamics; Maxwell–Lorentz electrodynamics; electromagnetic field; ontology of physics; philosophy of physics; Purcell; electromagnetic induction; self-induction; Aharonov–Bohm effect; electromagnetic radiation