Jones Beene wrote:
----- Original Message ----- From: "Stephen A. Lawrence"
I've recused myself from all technical debates on the reality or
possibility of OU magnetic motors until I come up with a good answer
to the following question:
When an electron is accelerated in a nonuniform magnetic field due to
the electron's own (permanent) magnetic dipole, where does the energy
come from?
Depends on how many layers deep to you need to go, Neo. This can be one
deep rabbit-hole, especially when you forget your meds...
I can recognize that this is a quote but I don't know the source, sad to
say. (It's not nearly old enough...)
On one lower level there is the well-known prhenomenon of magentic
precession of domains in a permanent magnet (PM), no?
Precession involves angular momentum, no?
But this isn't an angular momentum issue, this is a kinetic energy issue.
For simple electric charges, charge densities, and currents, by
inspection of Maxwell's equations, magnetic fields do no work, electric
fields are conservative, and a magnet-based perpetual motion machine
based on "simple" charge carriers is impossible.
But electrons aren't simple electric charges, and if the electron's
dipole isn't exactly perpendicular to the B field it's in, and if the
field is nonuniform, the electron will feel a (linear) force acting on
it, either up or down the field gradient depending on its orientation
relative to the field. And as soon as it starts to move, it's gained
kinetic energy.
The energy came from _somewhere_. But where? And can the source of the
energy be described by a model which uses a (conservative)
potential-based force field to describe the motion of the electron?
If the answer to that last question is "yes", then AFAICS magnetic
perpetual motion is, again, impossible (unless there is yet some other
strange and unknown way to squeeze energy out of a B field). If the
answer is "no" then the jury's out.
And I don't know the answer.
I asked one physicist about it and got a Zen-like answer which didn't
tell me much of anything.
For what it's worth, the disconnect with classical theory is that you
can't slow down the electron's spin. In a classical current loop, if
you do something that at first glance pulls energy out of noplace, close
examination generally reveals that you actually stole energy from the
loop. But, as I said, with an electron's permanent B field, you can't
do that.
Angular momentum can be transfered, no?
If a PM is capable, at the domain level, of transfering some of its
precessional angular momentum away from its aligned and synchronous
domains- then that would necessarily be a conservative situation... and
the magnet would/should become demagnetized... unless ??
Since this issue comes up with two electrons, each immersed in the
other's field, and since an electron can't be demagnetized, I think the
issue of "robbing the permanent magnet" to pay for the deficit is a red
herring.
