Brian,

Hullo?

Are you returning to dispute about that which I said you are in error,
or does it stand that you have been corrected by me (yet again)?

"gareth" wrote in message
...
"Brian Reay" wrote in message
...

Another name for the Magnetic Vector Potential is curl,

That's not correct. Curl is a vector field function applicable to many
things, and you have to have the curl of something.

which is key to understanding it, as there is also a Magnetic Scalar
potential. Confuse the two and you will never understand them.

39


Back the Magnetic Vector Potential under the name of curl. Curl is used
in 3D Vector Calculus (essentially calculus applied to the three
orthogonal components of a vector) and is referred to as a vector
operator. Importantly, it is only applied to rotating vectors

That is very misleading. The flow in a stream has curl when the
middle of the stream flows faster than the edges, but the individual
flow vectors are linear and not rotating.


and, like like all calculus, assumes infinitesimally small changes (in
this case rotation). The curl is found by applying the curl operator, and
it yields a vector represents the instantaneous direction and rate of
change of the Magnetic field.

That is misleading as well. A linear magnetic field moving through
a medium of varying permeability will have a spatial rate of change but
it will not be revealed by curling.


Thus, the Magnetic Vector Potential is a vector which represents the
instantaneous rate of change in the magnetic field.

That is complete nonsense. "Instantaneous" refers to a time element,
whereas curl is a spatial operator.


It is a vector as it has "direction" (as magnetic fields have directions)
and magnitude. It is a rate of change as the curl operator is a
differential operator, applied to the 3 components of rotating vector.


Note: In this context, the rotating vector may be generated by a
sinusoidal current in a coil as identical to one generated by a true
rotating magnetic field


No doubt the OP will criticise the above but that is up to him. It should
have been covered in a telecomms degree. The calculus, although in 3D, is
actually minimal, in that it is applied independently and so is really A
level (or O level for us oldies).


39

Quite a lot of blustering there, OM, but my question related to a visual
representation of the phenomen. Perhaps your much-noted need to
jump in with snide remarks over-rode your technical research via google?