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Toroidal ring model
The Toroidal Ring Model, known originally as the "Parson Magneton" or "magnetic electron", is also known as the "plasmoid ring", "vortex ring", or "helicon ring". This physical model for elementary electrons and protons was first proposed by Alfred Lauck Parson in 1915.
Additional recommended knowledge
Instead of a single orbiting charge, the toroidal ring was conceived as a collection of infinitesimal charge elements, which orbited or circulated along a common continuous path or "loop". In general this path, "vortex", or "fiber" of charge could assume any shape, but tended toward a circular form due to internal repulsive electromagnetic forces. In this configuration the charge elements circulated, but the ring as a whole did not radiate due to changes in electric or magnetic fields since it remained stationary. The ring produced an overall magnetic field or "spin" due to the current of the moving charge elements. These elements circulated around the ring at the speed of light c, but at frequency ν = c/2πR, which depended inversely on the radius. The ring's inertial energy increased when compressed, like a spring, and was also inversely proportional to its radius, and therefore proportional to its frequency ν. The theory claimed that proportionality to be Planck's constant h, the conserved angular momentum of the ring.
According to the model, electron or proton particles could be viewed as "bundles" of fibers or "plasmoids" with total charge ±e. The electrostatic repulsion force between like charge elements was balanced by the magnetic attraction force between the parallel currents in the fibers of a bundle, per Ampère's Law. These fibers twisted around the torus of the ring as they progressed around its radius, forming a Slinky-like helix. Circuit completion demanded that each helical plasmoid fiber twisted around the ring an integer number of times as it proceeded around the ring. This integer requirement was thought to account for "quantum" values of angular momentum and radiation. Chirality demanded the number of fibers to be odd, probably three, like a rope. The helicity, "right-handed" or "left-handed" direction of the twist, was thought to distinguish the electron from the proton.
The toroidal or "helicon" model did not demand a constant radius or inertial energy for a particle. In general its shape, size, and motion adjusted according to the external electromagnetic fields from its environment. These adjustments or reactions to external field changes constituted the emission or absorption of radiation for the particle. The model, then, claimed to explain how particles linked together to form atoms.
The development of the helicon or toroidal ring began with André-Marie Ampère, who in 1823 proposed tiny magnetic "loops of charge" to explain the attractive force between current elements. In that same era Carl Friedrich Gauss and Michael Faraday also uncovered foundational laws of electrodynamics, later collected by James Clerk Maxwell as "Maxwell's Equations". When Maxwell expressed the laws of Gauss, Faraday, and Ampère in differential form, he assumed "point particles", particles of no size, an assumption that remains foundational to relativity theory and quantum mechanics today. In 1867 Lord Kelvin suggested that the vortex rings of a perfect fluid discovered by Hermann von Helmholtz represented "the only true atoms." Then shortly before 1900, as scientists still debated over the very existence of atoms, J. J. Thomson and Ernest Rutherford sparked a revolution with experiments confirming the existence and properties of electrons, protons, and nuclei. Max Planck added to the fire when he solved the blackbody radiation problem by assuming not only discreet particles, but discreet frequencies of radiation eminating from these "particles", "oscillators", or "resonators", as he termed them. Planck's famous paper, which incidentally calculated both Planck's constant h and Boltzmann's constant k, suggested that something in the "resonators" themselves provided these discreet frequencies.
The Parson Magneton
In 1915 Alfred Lauck Parson proposed his "magneton" as an improvement over the Bohr model, depicting finite-sized particles with the ability to maintain stability and emit and absorb radiation from electromagnetic waves. About the same time Leigh Page developed a classical theory of blackbody radiation assuming rotating "oscillators", able to store energy without radiating. Gilbert N. Lewis was inspired in part by Parson's model in developing his theory of chemical bonding. Then David L. Webster wrote three papers connecting Parson's Magneton with Page's "oscillator" and explaining "mass" and alpha scattering in terms of the "magneton". In 1917 Lars O. Grondahl confirmed the model with his experiments on free electrons in iron wires. Parson's theory next attracted the attention of Arthur Compton, who wrote a series of papers on the properties of the electron,     and England's H. Stanley Allen, whose papers also argued for a "ring" electron.  
The aspect of the Parson's magneton with the most experimental relevance (and the aspect investigated by Grondahl and Webster) was the existence of an electron magnetic dipole moment; this dipole moment is indeed present. However, later work by Paul Dirac and Alfred Landé showed that a pointlike particle could have an intrinsic quantum spin, and also a magnetic moment. Therefore, in the modern theory, unlike the classical theory Parson used, the electron does not need a ring current to generate a magnetic dipole moment. The highly successful Standard Model of particle physics incorporates a pointlike electron with an intrinsic spin and magnetic moment.
The question of whether the electron has a substructure of any sort must be decided by experiment. All experiments to date agree with the Standard Model of the electron, with no substructure, ring-like or otherwise. The two major approaches are high-energy electron-positron scattering  and high-precision atomic tests of quantum electrodynamics , both of which agree that the electron is pointlike at resolutions down to 10-20 m, ruling out the Parson model which predicted a structure 10-11 m across.
Despite some superficial similarities, early-20th century ring models have no relationship to the modern string theory.
|This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Toroidal_ring_model". A list of authors is available in Wikipedia.|