"gareth" wrote in message
...

Also, what of a visualisation of the Magnetic Vector Potential, "A"?


This was something that I puzzled over for years, because in my Uni
textbooks it was introduced out-of-the-blue, but without any preamble
and was therefore difficult to see how it came in (understanding first,
maths second!)

The revelation came, probably about 20 years after studying all that
stuff at Uni, when I was standing close to the platform edge when
a fast train went through, and the dust devils from that passing, as
well as being at ground level, were also in vortices in the air,at which
point it became clear in my mind.

We have many models for what is happening in electrickery, and all
of them are incomplete, or just plain wrong, so it is perhaps surprising
that any tyro can progress!