Electric Dipole Radiation from a Spinning Current Loop

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SUMMARY

The discussion focuses on calculating the electric and magnetic dipole radiation fields from a rotating circular current loop with a constant current I and angular frequency ω. The magnetic dipole moment is defined as m = IA(cos(ωt) î + sin(ωt) ĵ), as derived from the loop's geometry and current. The challenge presented is determining the electric dipole moment, which is complicated by the absence of time-varying charge densities in the current distribution. The user questions the implications of a zero electric dipole moment in this context.

PREREQUISITES
  • Understanding of electromagnetic theory, specifically dipole radiation.
  • Familiarity with the concepts of magnetic dipole moment and electric dipole moment.
  • Knowledge of circular current loops and their properties.
  • Proficiency in using Jackson's classical electrodynamics equations.
NEXT STEPS
  • Study the derivation of electric dipole moments in current distributions.
  • Explore the implications of zero electric dipole moments in electromagnetic radiation.
  • Learn about the radiation fields associated with magnetic dipole moments using Jackson's equations.
  • Investigate the relationship between angular frequency and radiation patterns in rotating current loops.
USEFUL FOR

This discussion is beneficial for physics students, electrical engineers, and researchers interested in electromagnetic radiation, particularly those studying dipole radiation from current-carrying loops.

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Homework Statement


Hi everyone,

My problem is fairly simple: We have a circular current loop enclosing area A, and with a constant current I. The loop is rotating about its diameter at a constant angular frequency \omega. All we need to do is find the electric dipole, and magnetic dipole radiation fields.

Homework Equations


\vec{m}=IA \hat{n}=IA(cos(\omega t) \hat{x}+sin(\omega t) \hat{y})

\vec{p}=\int \rho (r',t) r' d^3 r'

The Attempt at a Solution


[/B]
For this particular problem, the magnetic dipole moment is very easy to find:
\vec{m}=IA \hat{n}=IA(cos(\omega t) \hat{x}+sin(\omega t) \hat{y})

Then using this you can easily plug it into the formulas outlined by Jackson to find the B, H, S fields corresponding to magnetic dipole radiation.

However, my problem is the electric dipole moment. How would you go about finding this? There are no "charge densities" moving around in time, only current distributions..

Thanks in advance!
 
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This might be too easy, but what would be wrong with a dipole moment of zero?
 

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