Longitudinal "Rays"

[HRS]

Would it, in pure theory,be possible to send a longitudinal wave through a material at such a rate that the waves have a frequency so high that it is comparable to the frequency of gamma or cosmic waves? And what would the result be on that material? I would be concerned about the vibration ensuing would literally tear the material apart in manner similar to ultrasound shattering glass or pulversing kidney stones. Or would the energy transfer and vibrations cause the material to simply heat up?

Edited April 26, 2014 by HRS

[studiot]

The velocity of sound in a given material is largely independent of frequency.

 

Further, whilst the frequencies attainable in ultrasonics have some overlap with the lower end of EM radiation frequencies, they do not reach that of gamma radiation.

Edited April 26, 2014 by studiot

[HRS]

But are there physical limitations that prevents longitudinal waves from reaching such frequencies?

[studiot]

 

Posted Today, 05:02 PM

But are there physical limitations that prevents longitudinal waves from reaching such frequencies?

 

I don't know.

 

To have a capability to excite a wave of a given frequency you have to have a viable (in theory) mechanism for excitation.

 

I can't think of one can you?

[HRS]

No just a thought experiment at best. It would seem mechanically impossible to me if you want to form it in a manner like any other longitudinal wave. Perhaps but I couldn't imagine it.

 

I was just imaginining the ramifications of the thought.

[studiot]

This is like saying,

 

"If I had a pocket cold fusion device I could make a lot of cheap electricity" and concentrating on the easy bit - the design of the electricity generator part.

 

Try this estimate.

 

Take a simple harmonic oscillator and calculate the maximum particle velocity at a range of frequencies, perhaps on a spreadsheet.

 

Since the vibrating molecule is an object with mass, relativity provides an upper limite of this vibrational speed and therefore velocity.

 

I think, however, that for all known materials, the vibrational energy would exceed the bond energy long before this limit was reached, so you would also have to postulate a super material where this was not so.

[Enthalpy]

One absolute limit to sound wavelength is the distance between atoms. It limits sound in air to <<1MHz and in solids to a few GHz - such frequencies are indeed used in nondestructive testing. This is very, very far from visible light (500THz) and gamma rays (again 100,000 times more).

 

Many loss mechanisms can, and use to, limit the frequency much earlier than the interatomic distance does.

[swansont]

You should probably look at the Debye frequency

 

https://en.wikipedia.org/wiki/Debye_frequency