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!

Vector potential

  1. Aug 16, 2007 #1
    i am having trouble visualiszing what vector potential A means physically. I understand that if you take the curl of it it give you the magnetic field B. I was wondering if anybody could also direct me to a website or show me a proof of how the electric field E is equal to the partial derivative of A with respect to time minus the grad of the scalar potential. I have no clue where to find that proof and neither do i possess a text book that has the proof in it.
  2. jcsd
  3. Aug 16, 2007 #2


    User Avatar
    Gold Member

    I still don't understand the physical significance of A. My teacher told me there wasn't really one... it was just a mathematical relationship. Anyway, it seems to be in the same direction the E field that gets induced by the B field (which may or may not be induced by an original field, E1)

    how E = dA/dt:

    use Maxwell's Equations, maybe the divergence theorem or one of those other integral forms.... I'm having deja vu:

  4. Aug 16, 2007 #3
    Your teacher is right on this one. The A-potential is introduced in the EM formalism to write the theory in a symmetrical way. It makes the step towards field theory more logic in the sense that the A field plays the role of the EM gauge field. Also, this potential is used to impose gauge-conditions to set the remaining degree of freedom that arises due to the definition of the A-field.

    More here : http://en.wikipedia.org/wiki/Magnetic_potential


    edit : you should also wonder about the question why they call the A field a POTENTIAL ! :wink: (hint : look at the definition of the scalar potential)
    Last edited: Aug 16, 2007
  5. Aug 16, 2007 #4
    Last edited by a moderator: May 3, 2017
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook