Hydrodynamic Electromagnetism: Maxwell's Equations in an Effective, Inviscid Medium (Non-Viscous Ether Analogy)

This preprint proposes an effective-medium interpretation of classical electromagnetism within the broader Hydrodynamic Quantum Gravity programme. The aim is not to claim experimental confirmation of a literal mechanical ether, but to present a coherent mapping in which vacuum electromagnetism is described as dynamics of an inviscid effective medium (an “ether” only in the historical, analogue sense) consistent with the standard Maxwell structure. The manuscript addresses common objections historically raised against medium-based interpretations—most notably transverse polarisation, Lorentz invariance, the observed value of the fine-structure constant, and the empirical success of quantum electrodynamics—by outlining specific mechanisms or correspondence claims and clearly distinguishing what is derived within the proposed mapping from what remains conjectural or out of scope. This reformulation does not attempt to replace Quantum Electrodynamics (QED) as a calculation framework. Rather, it offers a candidate physical ontology compatible with an effective-field description: a translation table is provided between hydrodynamic variables (pressure, vorticity, phase) and electromagnetic quantities (E, B, charge, current), with proposed tests and explicit open questions identified throughout. Related preprints: Gravity as Acoustic Radiation Pressure (DOI: 10.5281/zenodo.18646470); Gravity as Pressure Gradient (DOI: 10.5281/zenodo.18652098).