We are often habituated to see "dispersive waves in media" and "waves in dispersive media". So, a natural fundamental question arises in our mind. What is, or are dispersive in nature - "wave", "medium", or "both"?
This expression means that the propagation speed (and wavelength) of waves in a medium depends on the frequency of the wave.
Since the medium is the cause of dispersion, and the wave is dispersed, I think "dispersive medium" and "dispersed wave" are the correct phrases.
Dear karmakar
As you may know, due to known and valid mathematical models to describe the "nature" the wave which carrying energy throughout the "medium" interact with its structure, the scale of this interaction is highly dependent on relative size of the elementary "elements" of the "medium" and the wavelength of the "Wave".
for example the electrical permeability of a "medium" which is responsible to regulate the "medium's" behavior against introduced electrical field is highly dependent on frequency of the varying electrical field.
this means the behavior of the "medium" is dependent of the frequency of introduced wave. so the "Dispersion Medium" is true.
Best regards
Ahmad
Long ago, when I was still a physicist, I have studied nonlinear dispersive waves on the surface of water, with an application to tsunami. (you can still find my article here: Conference Paper Evolution of long nonlinear waves on shelves
). Then dispersive terms were obtained from the original system using asymptotical methods of expansion. Water by itself is not a dispersive medium in this case, but surface waves are dispersive because the speed of different frequencies depends on thinkness of a layer (depth).There are also dispersive media. Recall a school example of light passing prisma - with the spectrum. This happens because different frequencies (colors) propagate with different speed.
Probably, the answer to your question is "both", but I am not 100% sure.
Respected Yuri Yegorov ,
Thanks a lot for for your positive answer and the article.
Dear Karmakar,
These phenomenon result both from the nature and the rate of heterogeneities distribution versus the wavelength (frequency) of propagated wave
A wave is not dispersive - it is the medium. On the surface of water it is the air-water interface which is the dispersive medium.
I think Joerg's description is right.
Also, a sine wave is not dispersed - it only has one wavelength. Signals that are not sine waves are dispersed in dispersive media because they contain more than one frequency. Non-linear effects on dispersion can result in signals not being dispersed, for eqample solitons, but I'm not sure if this is relevant to your question.
Prove that it is a wave, not a medium, that is dispersive alongside judicious examples.
In most cases, dispersion is a mutually cooperative and relative property of both wave and its propagating medium.
In other words, both the wave and its propagating medium could be dispersive in real nature.
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