Layman explanation of some simple EM equations

  • #1
864
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Main Question or Discussion Point

So its been a while since I studied maxwells equations, anyway:
equations.png

So From my ignorant perspective, trying to derive conceptual meaning from these, I can see that the time dependant study there is some conductivity x the partial differential of the magnetic vector potential plus the cross product of mu*B which is H minus SOMETHING? equals the electron current density.

I don't really remember what the magnetic vector potential is (well, that is to say, I remember not really understanding it when I tried learning about it in the first place), or the last term....or what the cross product of H is.
I'm at a similar loss regarding the Frequeny Domain study.

To be honest all I really remember about the cross product is that it is perpendicular to the two vectors being multiplied.


If any one can offer a more indepth explanation of these formulas in English, I mean some maths is fine, but for a layman, that'd be great.

Cheers!!
 

Answers and Replies

  • #2
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These might help
 
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  • #3
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These might help
Thanks for the reply, the second vid was a good refresher about curl (and to a lesser extent divergence), The first one didn't tell me anything I didn't already remember, but it made me try and wonder how Faraday's law might fit into those equations? (given that it has a current and cross product of B in it too).
But I'm still none the wiser about what the 'v' is in that equation (velocity?) or what the curl of H, cross product of Bxv and partial derivetive of A have to do with current density??

Cheers!
 
  • #4
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So am I to assume that these equations aren't a modification/application of one specific Maxwell equation??
 
  • #5
jtbell
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What is the context of those equations? Where did you see them?

They seem to have something to do with electric and magnetic fields and electric currents in conductors. σ is the usual symbol for electrical conductivity, which is the reciprocal of resistivity: σ = 1/ρ.
 
  • #6
864
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What is the context of those equations? Where did you see them?

They seem to have something to do with electric and magnetic fields and electric currents in conductors. σ is the usual symbol for electrical conductivity, which is the reciprocal of resistivity: σ = 1/ρ.
Yeah, they're from Comsol Multiphysics, depending on if you're simulating something that varies over time etc.
 

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