| aside sci-fi and Maxwellian formulae characterizations, there was no requirement for calling magnetism, a primary force |
We can estimate common magnetism from the electrodynamics, summarizing here--
PARALLEL WIRES: consider the flow of electrons in two parallel wires: each passing electron impinges on the extended fields of each individual nucleon-proton and electron in the adjacent wire - and deflects. Where there is no systematic flow in the second wire, the electrons in the first wire impinge balancedly: the electron-proton impingements attract, and the electron-electron impingements repel, cumulatively equally: and there is no net force: no systematic deflection. [Impingements also equalize Fermi-temperatures] Where there is systematic opposition flow, the electron-electron impingements are faster, more frequent: and repulsion cumulatively exceeds electron-proton attraction - there is systematic deflection, and the wires repel. Where the currents flow in systematic conjunction, the electron-electron impingements are slower, less frequent: and repulsion is cumulatively exceeded by electron-proton attraction - there is systematic deflection [mutually toward], and the wires attract.
TRANSFORMER WIRES: consider the application of an electric potential to the primary of a transformer (coil) wire: an opposite charge develops in the adjacent secondary wire - then the flow of electrons in the primary increases the Fermi-temperature in the secondary proportionably to the excess - and a restoration current flows: back-out the secondary.
SELF-INDUCTION WIRES: similar, but a current must flow.
[However, there is a -secondary- direct magnetic force-line similarly qualified in sub-leptonic quantum-helicity charge-winding flow]
This article was done in development of a project SesQuaTercet movie-story.