Electromagnetic radiation and the self torque of an oscillating magnetic dipole

Masud Mansuripur, Per K. Jakobsen

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

A uniformly-charged spherical shell of radius R, mass m, and total electrical charge q, having an oscillatory angular velocity Ω(t) around a fixed axis, is a model for a magnetic dipole that radiates an electromagnetic field into its surrounding free space at a fixed oscillation frequency ω. An exact solution of the Maxwell-Lorentz equations of classical electrodynamics yields the self-torque of radiation resistance acting on the spherical shell as a function of R, q, and ω. Invoking the Newtonian equation of motion for the shell, we relate its angular velocity Ω(t) to an externally applied torque, and proceed to examine the response of the magnetic dipole to an impulsive torque applied at a given instant of time, say, t = 0. The impulse response of the dipole is found to be causal down to extremely small values of R (i.e., as R → 0) so long as the exact expression of the self-torque is used in the dynamical equation of motion of the spherical shell.

Original languageEnglish (US)
Title of host publicationPlasmonics
Subtitle of host publicationDesign, Materials, Fabrication, Characterization, and Applications XVIII
EditorsDin Ping Tsai, Takuo Tanaka
PublisherSPIE
ISBN (Electronic)9781510637306
DOIs
StatePublished - 2020
EventPlasmonics: Design, Materials, Fabrication, Characterization, and Applications XVIII 2020 - Virtual, Online, United States
Duration: Aug 24 2020Sep 4 2020

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
Volume11462
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X

Conference

ConferencePlasmonics: Design, Materials, Fabrication, Characterization, and Applications XVIII 2020
CountryUnited States
CityVirtual, Online
Period8/24/209/4/20

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering

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