As you know I have no reputation to uphold so I can freely speak from
ignorance in these matters.
There seems to be a great gnashing of teeth and searching for straws
over what might be a relatively simple phenomenon ( I am only good at
simple phenomenon so that is what I look for). This little bit of magic
that has the electron's feet mired in dielectric goo is certainly not a
very strong force because it can easily be overcome by a little
friction. It may even be unlikely that it is some mysterious force such
as those that have been found lurking within the nucleus.
The same explanation might even show why some surfaces are "electron
slippery" and others are not.
I am not smart enough to figure it all out, and my slow ponderings on
the matter will not be completed for several months to come, so while
the thread is still active, I will simply present my much less than half
baked idea to you as a "for what its worth".
It seems reasonable to me that at the boundary of a solid there must be
a considerable discontinuity (conventional meaning). The atoms at the
edge must live a very lopsided existence. Because of the nature of
atoms, and the space between them, this edge phenomenon probably extends
to other atoms some ill defined distance into the material. A lopsided
existence seems to remind me of something I once read about atoms in a
permanent magnet.
If the distorted electron orbits of these edge atoms are such that they
produce a magnetic pole, all sorts of interesting atomic sized effects
could be taking place. I suspect that these edge atoms orbits are
randomly orientated in a way that there is no net macroscopic,
measurable magnetic field.
At the atomic level however, a free electron, which had been buoyed to
the surface by who knows what repulsive forces, may find a particular,
edge generated, atomic sized, magnetic field to be rather large (in
size, not necessarily in strength) at any one local point. (I envision
something like the surface of my pebble strewn front walk with a speck
of dust hovering over it). If the speck (our electron) tries to move, it
produces a magnetic field of its own and may even spiral around in
circles.
I have no idea of what happens to individual charges (electrons), but I
can imagine them playing some giant three dimensional, statistical game
of billiards, but are nevertheless bound to the surface wherever they
go.
There must be some differences in the surface magnetic bumps between
conductors and dielectrics. Possibly the dialectic have magnetic fields
that have fences around them, or maybe they are separated by distance,
or maybe "focused" (whatever that implies) in a way that the free
electrons cannot easily traverse the gulf between them and the free
electrons tend to cluster in little spiraling domains above singular
atoms.
On the other hand, conductors might have edge generated magnetic fields
that are fused into a mosaic on which the spiraling electrons skate
freely, or in concert with natural equilibrium of charges. They are
nevertheless bound to the surface by the weak magnetic attraction
produced by their own movement in concert with the magnetic field of the
individual atoms below them.
As I said at the start, this is pure conjecture and intuition on my
part. I just don't believe that one has to go very far to explain
something that is so natural and ubiquitous in our wonderful world.