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Image charge method to find Green's function

  1. Oct 23, 2014 #1
    hi guys,
    my professor told me in the class that when we would like to determine green function there are two general method i.e using image charge and using orthonormal eigen function. However I don't understand what are the specific differences between them. Anybody can help me? Moreover in the problem systems that solved by using image charge (as far as I have seen), there is always point charge there. Can image charge method be used in a problem like finding green function in a space (without charge) between 2 infinite parallel conducting plates for example?
  2. jcsd
  3. Oct 23, 2014 #2


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    Can you give an example of finding Green's function by either method?
  4. Oct 23, 2014 #3
    That's why I am asking, can we use both of them for same problem or not ?
  5. Oct 23, 2014 #4


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    The Green's function is defined as the potential due to a point charge with all surfaces grounded.
    The image charge method is difficult to use for 2 parallel plates, because that requires an infinite set of image charges.
  6. Oct 23, 2014 #5
    Oh unfortunately I have a task to solve it usi b g image charge
  7. Oct 24, 2014 #6


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    The only difference between the two methods is that the image-charge method is not always applicable in practice. Of course, at the end you get the same result with both methods when applicable. It works for the half-plane and the sphere straight-forwardly. For two parallel plates I think you can use it, introducing an infinite series of image charges and summing up their contributions.

    Since this is a typical home-work problem, you should ask this question in the homework section.
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