November 10, 2014 Jackson’s Electrodynamics Michelle While USD

Electrical and Magnetic Energy propagates through vacuum and media via waves Media properties affect wave speed (frequency) which make dielectric (  ) and magnetic (  ) susceptibilities dependent upon frequency of the EXTERNAL EM energy Poynting’s Theorem utilizes conservation of energy to determine how energy is lost within a medium. Summary

Atoms within substances move. They exhibit thermal agitation, zeros point vibration and orbital motion which gives rise to internal frequencies of the substance, however, these motions average out so only EXTERNAL applied oscillators contribute to the frequencies exhibited by the material. Medium Characteristics 1.Linear or non-linear in nature 2.Isotropic or anisotropic 3.Non-dispersive with “no” energy losses or Dispersive with losses Background

Energy Losses

Linear and Isotropic Media

Dispersive Media

Dispersive Media-Energy Losses

Poynting’s Theorem

Jackson, John David, Classical Electrodynamics, 3 rd Ed. John Wiley & Sons, Inc. (1999). Griffiths, David J. Introduction to Electrodynamics, 4 th Ed. Pearson, NY (2013) Landau, L.D. and Liftshitz, E.M. Electrodynamics of Continuous Media Vol 8. 2 nd Ed. Pergamon Press, NY (1984). References