Abstract
The Spiral Structure Model (SSM) is a phenomenological model in the tradition of Bohr’s early atom: confined to kinematics and geometry, it exchanges dynamical depth for ontological clarity and experimental exposure. Three postulates suffice. (I) The photon is a pointlike energy quantum in uniform helical motion, its axial and circulation speeds both equal to c; (II) physical space is an elastic, relativistically covariant medium sustaining vortex excitations; (III) the electron is a stable topological vortex defect of that medium. From these — with every step carrying an explicit epistemic label — the model obtains the photon’s circulation angular momentum mcrγ = ℏ as a consistency theorem, identified with its spin; logarithmic vortex confinement with no free parameters; the two polarization states and the absence of a longitudinal mode; orbital angular momentum as an ensemble property; the electron’s 720-degree periodicity and spin ℏ/2 from π1(SO(3)) = Z2; the fine-structure constant as a ratio of structural scales; the free radiation field as a retarded ensemble moment satisfying the wave equation exactly; a phase-coupling account of two-slit interference; and a double-helix ontology of entangled pairs that reproduces the CHSH value 2√2. Three falsifiable discriminants are stated with explicit kill criteria: a wavelength-locked on-axis void in the photon’s detection profile, a spin-dependent electron form-factor window near Q = mc, and a circulation-periodic component in entangled-pair coincidence timing.