Wake Fields in the Electron Gas Including Transverse Response
Eric J. Cockayne, Zachary H. Levine
Relativistic electrons have transverse electric fields comparable in magnitude to the longitudinal fields. We determine the relative effects of transverse and longitudinal fields of a moving point charge on the dielectric response of a uniform electron gas, using Lindhard's longitudinal and transverse dielectric functions and, separately, the Drude dielectric function. In the direction of motion, the transverse wake fields are approximately -v2/c2 times the longitudinal wake fields. The stopping power, as determined by applying Poynting's theorem, is reduced. Perpendicular to the direction of motion, the transverse wake fields are small compared to the longitudinal fields. Electromagnetic fields of a moving point charge are given in Fourier space for the Lorentz, Hamiltonian, and Coulomb gauges.
Physical Review B (Condensed Matter and Materials Physics)
EELS, fast electrons, Lindhard dielectric function, stopping power, transverse response