Surface wave
|
|
In physics, a surface wave is a wave that is guided along the interface between two different media for a mechanical wave, or by a refractive index gradient for an electromagnetic wave.
An example is the waves at the surface of water, ocean surface waves. Longitudinal and transverse motions of the surface particles combine to undergo a clockwise circular motion. As the depth into the water increases, the radius of the circles decreases. See: Animation of surface water wave (http://www.kettering.edu/~drussell/Demos/waves/water.gif). Another example is internal waves, waves that are transmitted along the interface of two water masses of different densities.
In seismology, several types of surface waves are encountered. See seismic wave.
Applications in telecommunications
- The field components of the wave diminish with distance from the interface.
- Optical energy is not converted from the surface wave field to another form of energy and the wave does not have a component directed normal to the interface surface.
- In optical fiber transmission, evanescent waves are surface waves.
- In radio transmission, ground waves are surface waves that propagate close to the surface of the Earth, the Earth having one refractive index and the atmosphere another, thus constituting an interface surface.
Source: from Federal Standard 1037C in support of MIL-STD-188
External links
- Surface Wave -- from Eric Weisstein's World of Physics (http://scienceworld.wolfram.com/physics/SurfaceWave.html)