1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

What is this version of the wave equation?

  1. Oct 28, 2015 #1
    I came across this expression for the wave equation:

    [tex]\nabla^2E + \mu\sigma\frac{\partial{E}}{\partial{t}} - \frac{n^2}{c^2}\frac{\partial{E}}{\partial{t^2}} = 0[/tex]

    My question is what kind of medium is it for/where did it come from?
  2. jcsd
  3. Oct 28, 2015 #2
    That is the equation of an electromagnetic wave passing through a conducting medium. You wrote the last term wrong. It should be the second derivative of the electric field. You will see it in any book on classical electrodynamics.
  4. Oct 28, 2015 #3
    Where does the refractive index come from?
  5. Oct 28, 2015 #4
    The medium has a refractive index and a conductivity.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook