Examples: Sound waves (pressure waves) in air (or in any gas or solid or liquid) Waves on a stretched string Waves on the surface of water "The Wave" at the ballpark stadium. The medium is the people. Electromagnetic waves (light) – this is the only kind of wave which does not require a medium. EM waves can travel in vacuum. This was quite a surprise to 19 th century physicists who had trouble ...

The dielectric susceptibility of a wide class of dielectric materials follows, over extended frequency ranges, a fractional power-law frequency dependence that is called the ‘universal’ response. The electromagnetic fields in such dielectric media are described by fractional differential equations with time derivatives of non-integer order. An exact solution of the fractional equations for a ma...

We present a general theory of three-dimensional non-paraxial spatially-accelerating waves of the Maxwell equations. These waves constitute a two-dimensional structure exhibiting shape-invariant propagation along semicircular trajectories. We provide classification and characterization of possible shapes of such beams, expressed through the angular spectra of parabolic, oblate and prolate spher...

We consider the symmetry in the interaction of photons and electrons, which has led to a common description of electron and photon accelerations; effects such as photon Landau damping arise naturally from such a treatment. Intense electromagnetic waves can act as a photon mirror to charged particles. The subsequent acceleration is equivalent to the photon pulse accelerating electrons. During th...

We report the first experimental demonstration of time-reversal focusing with electromagnetic waves. An antenna transmits a 1-micros electromagnetic pulse at a central frequency of 2.45 GHz in a high-Q cavity. Another antenna records the strongly reverberated signal. The time-reversed wave is built and transmitted back by the same antenna acting now as a time-reversal mirror. The wave is found ...

Understanding electromagnetic wave phenomena is very important to be able to design RF cavities such as for atmospheric microwave plasma torch, microwave vacuum oscillator/amplifier, and charged-particle accelerator. This chapter deals with some electromagnetic wave equations to show applications to develop the analytic design formula for the cavity. For the initial and crude design parameter, ...