What causes the potential energy in non-submerged electrons?

[jaydnul]

I am not asking for a simplification or new way of analyzing circuits! Take this hypothetical situation:

I am given the task of raising the potential difference across a device to the value x. Theoretically I could create a generator; I know that moving charge in a magnetic field will create an emf. The magnetic field causes the electrons to have a higher potential. But I still don't know how the electrons are going to leave the magnetic field and out into more wire (where there is no magnetic field to raise their potential).

Now I'm asking what causes the electrons who aren't submerged in the magnetic field to have a higher potential energy. We've already established that electron on electron interactions don't, as well as excess charge on the surface. So what causes this higher potential in the non-submerged electrons? You said it here:

It takes two to tango and it is the relationship between an electron and with all the other charges and fields around that gives it Potential Energy.

I'm just asking for an extrapolation of this. What charges and what fields?

Edit:
I realize that referencing another forum post is not the most rigorous proof, but the answerer here also seems to think that excess charge on the surface of the metal is responsible for the electric field that pushes the electrons. mfb, please look at this and explain to me why they are also incorrect:

http://physics.stackexchange.com/questions/17741/how-does-electricity-propagate-in-a-conductor

 

[sophiecentaur]

What charges and what fields?

I meant the whole caboodle - charges of the local charged particles and the magnetic and electric fields of the whole system and the way all that is modified by the presence of our electron and what it's doing. It's not useful to take an electron in isolation (in this sort of context).
I looked at that link and it proposes what looks to me like a novel idea without support from references. If you want to clear this up, you should really be reading more mainstream stuff to avoid further confusion.
I don't always quote references when my source is mainly from mainstream textbooks - but that link is not textbook stuff; it's a personal view.

I have just thought of a clincher argument about this. Electrons, in the solid state, are essentially Quantum Particles. They do not behave in a classical way and the whole of this thread has been assuming they do. It is not surprising that trying to describe a QM phenomenon in classical terms doesn't get us far. I think that should let you off the hook when you feel you should be able to explain this sort of situation in this particular way.

 

[jaydnul]

I realize it's a quantum system, but energy is still conserved. At one moment you're saying that the emf in the wire IS induced by local charged particles and the electric and magnetic fields of the whole system, and the next moment you're saying it is an invalid question because the electrons behave quantum mechanically. The reason I am being so persistent is because we have explanations like this for some parts, and then other parts we say that it is an invalid question. I'll illuminate that point by asking one more time in the following fashion (and then I'll stop haha).

Please help me answer the second question:
Q1. Why do the electrons in a wire feel a force when inside a generator?
A: They are moving relative to a magnetic field which induces an emf and raises their potential energy. Edit: Relative to some reference voltage (didn't want to get picked up on that )
Q2: Why do the electrons in a wire feel a force when outside a generator (but connected to the wires that are inside the generator)?
A:?

Do we not know? Is it as simple as that? You said local charged particles and the electric and magnetic fields of the whole system. Great, but those charged particles and electric/magnetic fields must undergo a change from their initial (unconnected wire) state in such a way that corresponds to the change in potential; if no charge moved around, or if no electric field changed in magnitude, nothing would happen in the wire.

BTW, the first link I posted was from a (what I thought) mainstream textbook. Though it looks like it was written by the same people who published that website...

 

[Dale]

I'm just asking for an extrapolation of this. What charges and what fields?

Why would you bring fields into a circuits class? Circuit theory doesn't use the concept of a field at all.

I would teach circuits first, and Maxwell's equations later and I would avoid bringing Maxwell's concepts into a circuits class as much as possible, except to mention that they exist and will be covered in later classes. I don't see the desire to complicate circuit theory nor to teach Maxwell's equations half way.

 

[jaydnul]

Why would you bring fields into a circuits class?

I'm not looking to do circuit analysis with this information. I see now that my first post would give this impression, but I'm motivated purely by curiosity at this point.

 

[jaydnul]

How about this. A battery has a net positive end and a net negative end. When you connect a wire in between them, The electrons in the wire are attracted to the positive end and repelled from the negative end. But as they leave the wire and onto the positive battery terminal, they leave behind the positive protons in the copper. This attracts more electrons from the negative battery terminal. This continues until the battery runs out of energy, which comes from the chemical reaction that does work to separate the charge.

Is that a correct explanation?

 

[Dale]

Now I'm asking what causes the electrons who aren't submerged in the magnetic field to have a higher potential energy. We've already established that electron on electron interactions don't, as well as excess charge on the surface. So what causes this higher potential in the non-submerged electrons? You said it here:

OK, since you are interested in fields and charges (outside of the context of a circuits class) and since you emphasized the word "causes", my answer would be Jefimenko's equations:

https://en.wikipedia.org/wiki/Jefimenko's_equations

Pay particular attention to the section about the retarded potentials.

The reason that I would go to Jefimenko's equations is that for A to cause B then A must happen before B. So a causal relationship is expressed by something of the form $B(t) = f(A(t'))$ where $t'<t$. Maxwell's equations are not of this form, so they cannot express a causal relationship. Jefimenko's equations are.