Re: Physics of Wireless Transmission

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: Vardan <vardan01@xxxxxxxxxxxxxxxxxxxxxxx>

Hi Stork,

At 10:08 AM 4/23/2006, you wrote:

> I'm sure Dave is refering to coherent movement of free electrons in 
> a permanent magnet rather than random movement of billions of 
> electrons. Coherent movement of electrons in a permanent magnet 
> would imply a current.  Can you experimentally measure the current 
> from the billions of electrons flying around in your 10,000G super magnet?
>
> Stork

I was thinking in objects external to the magnet itself.

It is possible to measure the electric fields of "still" atoms, but 
they cheat a bit with a varying magnetic field.  MRI uses magnetic 
fields to align magnetic dipoles without moving the atoms much in 
space.  Although they are not interested in currents (Current density 
imaging is not working yet) one could think real hard and probably 
figure some currents out from MRI data.

One would have to take classes from this guy:

http://www.cis.rit.edu/htbooks/mri/inside.htm

just reading the "table of contents" makes my brain hurt %:-)

If one wants to know way too much about fields, study this guy's 
on-line textbook...

One advantage MRI has is that they can charge a ton of cash every 
step of the way.  Thus, there are some super smart talented people 
working on it.  The state of the art there leaves most of us in the 
dust :-p  They seem to have taken the mathematics and field theory to 
quite an extreme!!  Electronics, math, fields, computer science, 
medicine all come together there...  An am not sure if they need to 
take relativity theory into account or not.  I would not be surprised 
if they did...

I wonder if one could study the effects of common items near a magnet 
and how they bend the magnetic fields and infer something about the 
spinning atoms in the items.  One could play with things like bismuth 
which is "diamagnetic".

http://en.wikipedia.org/wiki/Diamagnetic

Check out the floating frog!!  That is way T00 powerful of a magnet 
;-)))  His little atoms spinning and their currents make him 
float!!!  Knowing the weight of the frog and the magnetic field, you 
can figure out the average current from his electrons.  You don't 
quite know "how many" atoms are contributing, so there are a few 
unknowns for figure out precise numbers.

http://www.hfml.ru.nl/froglev.html

But the idea is you don't really have to have conventional current 
flowing through a wire to detect electrons even if they are just 
spinning inside a still atom.

Not very on-topic I guess...

Cheers,

        Terry