Wave propagation is any of the ways in which waves travel through a medium (waveguide). A wave is a disturbance that propagates through Space and Time, usually with transference of Energy. A transmission medium' (plural transmission media) is a material substance ( Solid, Liquid or Gas) which can propagate A waveguide is a structure which guides waves such as Electromagnetic waves Light, or Sound waves

With respect to the direction of the oscillation relative to the propagation direction, we can distinguish between longitudinal wave and transverse waves. Longitudinal waves are waves that have vibrations along or parallel to their direction of travel that is waves in which the motion of the medium is in the same direction as the motion A transverse wave is a moving Wave that consists of oscillations occurring perpendicular to the direction of energy transfer

Another useful parameter for describing the propagation is the wave velocity that mostly depends on some kind of density of the medium. Wave propagation is any of the ways in which waves travel through a Waveguide. The density of a material is defined as its Mass per unit Volume: \rho = \frac{m}{V} Different materials usually have different

For electromagnetic waves, propagation may occur in a vacuum as well as in a material medium. Electromagnetic radiation takes the form of self-propagating Waves in a Vacuum or in Matter.

Wave velocity

Seismic wave propagation in 2D modelled using FDTD method in the presence of a landmine

Wave velocity is a general concept, of various kinds of wave velocities, for an electromagnetic wave's phase and speed concerning energy (and information) propagation. Seismic waves are Waves that travel through the Earth, most often as the result of a tectonic Earthquake, sometimes from an Explosion Finite-difference time-domain (FDTD is a popular computational electrodynamics modeling technique Electromagnetic radiation takes the form of self-propagating Waves in a Vacuum or in Matter. The phase of an oscillation or wave is the fraction of a complete cycle corresponding to an offset in the displacement from a specified reference point at time t = 0 Speed is the rate of motion, or equivalently the rate of change in position often expressed as Distance d traveled per unit of The relationship between group velocity and phase velocity is the dispersion relationship:

The dispersion relation gives you the speed at which a point of constant phase of the wave will travel for a discreet frequency (hence phase velocity). The group velocity of a Wave is the Velocity with which the variations in the shape of the wave's amplitude (known as the modulation or envelope The phase velocity (or phase speed) of a Wave is the rate at which the phase of the wave propagates in space In Optics, dispersion is the phenomenon in which the Phase velocity of a wave depends on its frequency Dispersion relations describe the ways that wave propagation varies with the Wavelength or Frequency of a wave. The phase of an oscillation or wave is the fraction of a complete cycle corresponding to an offset in the displacement from a specified reference point at time t = 0 The phase velocity (or phase speed) of a Wave is the rate at which the phase of the wave propagates in space The speed at which a resultant wave packet from a broad range of frequencies will travel is called the group velocity and is determined from the gradient of the dispersion relation:

In almost all cases, a wave is merely a movement of energy through a medium. The group velocity of a Wave is the Velocity with which the variations in the shape of the wave's amplitude (known as the modulation or envelope In Vector calculus, the gradient of a Scalar field is a Vector field which points in the direction of the greatest rate of increase of the scalar Dispersion relations describe the ways that wave propagation varies with the Wavelength or Frequency of a wave.

Wave velocity is the speed at which the energy moves through this medium. The more dense a medium is, the faster the waves will travel as particles will be closer together and thus energy can be transferred among them at a greater rate.

The wave dispersion equation is:

where

v is the wave velocity ([LT ⁻¹]; m/s);

λ is the wavelength ([L]; m);

f is the frequency ([T ⁻¹]; Hz or ¹⁄_s);

T is the period ([T]; s);

ω is the angular frequency (rad Hz or ^rad⁄_s); and,

k is the wavenumber (^rad⁄_m). Frequency is a measure of the number of occurrences of a repeating event per unit Time. The hertz (symbol Hz) is a measure of Frequency, informally defined as the number of events occurring per Second. Do not confuse with Angular velocity In Physics (specifically Mechanics and Electrical engineering) angular frequency

See also

• photon
• polarization
• antenna theory
• propagation
• wave

References

• A Treatise on The Mathematical Theory of Elasticity, A. In Physics, the photon is the Elementary particle responsible for electromagnetic phenomena Polarization ( ''Brit'' polarisation) is a property of Waves that describes the orientation of their oscillations An antenna is a Transducer designed to transmit or Receive electromagnetic waves In other words antennas convert electromagnetic waves into A wave is a disturbance that propagates through Space and Time, usually with transference of Energy. E. H. LOVE, Dover Publications, New York.
• Dilbag Singh and S. K. Tomar, "Wave propagation in micropolar mixture of porous media" International Journal of Engineering Science, Volume 44, Issues 18-19 , November 2006, Pages 1304-1323.
• Weisstein, Eric W. , "Wave velocity".

External links

• Propagation of sound waves
• Animation How an electromagnetic wave propagates through a vacuum