Physics Van 3-site Navigational Menu

Physics Van Navigational Menu

Q & A: Standing waves in cylindrical cavities.

Learn more physics!

Most recent answer: 10/22/2007
Q:
Hello:

I have two questions on the same subject.

Question 1

Is it possible to have a cavity designed as two concentric conducting cylinders which are separated by a dielectric medium support a standing wave? Assume one possible source of the standing wave comes from background noise.

Question 2

Assuming the above is true, would the standing wave distort from being a sine wave to a fully rectified square wave if imposed upon by an external static magnetic field that lies parallel to the length of the concentric cylinders?

Sincerely,

Michael Maurice
- Michael Maurice
Barre, Vermont, USA
A:
#1  Yes, it's a well know problem in electricity and magnetism.   The solutions are combinations of Bessel functions, rather messy things.   The addition of a dielectric medium can be handled as well.  Yes, they can be excited by background noise if it is properly coupled into the cavity.

#2  No, a static magnetic field has no effect on the solutions. 

LeeH

Answer #2 above assumes that the magnetic field has no effect on the dielectric properties of the medium. Usually that's a decent approximation./ Mike W.

(published on 10/22/2007)

Follow-up on this answer.