Propagation of Electromagnetic Waves

Electromagnetic waves in vacuum are oscillations of electric and magnetic fields in the absence of radiation sources. This chapter considers the properties of electromagnetic waves in vacuum. If electromagnetic waves occur in materials, they are accompanied by oscillations of charged particles, that is, electrons and ions. These oscillation processes are more complicated. Electromagnetic waves in media are generally not transverse: the field vectors may have both the transverse and the longitudinal components, with respect to the direction of propagation. The exact solution of the problem on interaction of electromagnetic waves with conducting or dielectric bodies is reduced to the integration of Maxwell's equations subject to appropriate boundary conditions. X-rays, or Röntgen rays, are high-frequency electromagnetic waves with frequencies from ≈ 2 × 1023 to ≈ 2 × 1016 rad/s, that is, between the ultra violet radiation and gamma radiation.