Electromagnetic diffusion in anisotropic media
Article first published online: 8 FEB 2011
Copyright 2011 by the American Geophysical Union.
Volume 46, Issue 1, February 2011
How to Cite
2011), Electromagnetic diffusion in anisotropic media, Radio Sci., 46, RS1010, doi:10.1029/2010RS004402.(
- Issue published online: 8 FEB 2011
- Article first published online: 8 FEB 2011
- Manuscript Accepted: 4 NOV 2010
- Manuscript Revised: 19 SEP 2010
- Manuscript Received: 18 MAR 2010
 I present a plane-wave analysis of anisotropic electromagnetic media at the low-frequency range, where the displacement currents can be neglected and the field is diffusive. Anisotropy is due to the conductivity tensor and the magnetic permeability is a scalar quantity. The analysis includes the energy balance (Umov-Poynting theorem) and provides expressions of measurable quantities such as the phase and energy velocities, the attenuation factor, and the skin depth as a function of frequency and propagation direction. The balance of energy allows the identification of the stored and dissipated energy densities, which are related to the magnetic energy and the conductive part of the electric energy. For a real conductivity tensor, the stored energy equals the dissipated energy. I also establish fundamental relations, e.g., the scalar product between the slowness vector and the power-flow vector is equal to the energy density. For uniform plane waves, the phase velocity is the projection of the energy velocity vector onto the propagation direction and a similar relation is obtained by replacing the energy velocity with a velocity related to the dissipated energy. I have also obtained the Green function for an azimuthally isotropic medium (transverse isotropy), which is used to calculate transient fields.