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!

I Approximate a plane E&M wave with this large sum...

  1. Apr 8, 2017 #1
    I would like to approximate a plane electromagnetic wave with a very large sum of the following.

    Let an infinite line, say the z axis, have a electric polarization on that line and perpendicular to that line, say the x direction to be specific given by,

    P(z,t) = pcos(kz-ωt). The polarization is a function of both space and time. Now let there be a uniform density of such lines in all space all parallel to one another, all in phase, and with them all polarized in the x direction. Will such a construction approximate the electric and magnetic fields of plane E&M wave?

  2. jcsd
  3. Apr 11, 2017 #2


    User Avatar
    Gold Member

    I just cannot understand the question. How can we have polarisation on that line and also perpendicular to it?
  4. Apr 11, 2017 #3
    Just imagine at each point of the line a polarization vector that is also perpendicular to the line. Polarization is charge times a distance, just imagine the distance is very small, as small as you wish with charge increased so that distance times charge is a constant. Let the distance be of order the string length in string theory, that is pretty damn small.

    Sorry for the confusion.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted