There is indeed a different kind of force predicted by this approach,
as you suspected. I recommend that you look into it.

Google: "Weberian Electrodynamics"

Purcell has the right approach, but simply doesn't follow through
correctly.

Richard Perry

Sue... wrote:

h_v_ansari@yahoo.com wrote:

Hi all,

1. We know that diamagnets are repelled from dense magnetostatic
fields. In an investigation I need to know whether this repulsion
will increase or decrease or remain unchanged when the experiment
is performed in vacuum or inside a gas which its molecules have
no magnetic dipoles.

2. Also we know that two parallel wires carrying parallel electric
currents attract each other and if they carry antiparallel currents
they repel each other. The above-mentioned investigation
necessitates knowing whether this attraction or repulsion will
increase or decrease or remain unchanged when the experiment is
performed in vacuum or in a gas which its molecules lack
magnetic dipoles.

Since performance of the above-mentioned experiments is not
possible for me at present, I request anyone who has any
information in this respect or has the possibility to perform
these experiments to express the results of these experiments
in this thread or email them to my address:
hamidvansari<at>yahoo<dot>com or hvansari<at>gmail<dot>com
or let me know the sources from which I can get information
in this respect.

Best regards
Hamid V. Ansari

I have heard that these forces have something to do with
time dilation and length contraction as illustrated here:
http://physics.weber.edu/schroeder/mrr/MRRtalk.html

I've just had a look at
http://physics.weber.edu/schroeder/mrr/MRRtalk.html
I can't get past the following reasoning:
"it exerts an attractive electrostatic force on the test charge.
Back in the lab frame, we call this force a magnetic force"
This is from the section of content titled
"Magnetism as a Consequence of Length Contraction"

If this were the case then a voltage would be measured at the test
point relative to the wire.
He is literally claiming an electrostatic force is magnetism.

In fact we don't even use a test charge to measure magnetism. So the
whole setup seems false to me. In a static magnetic field the force on
a stationary test charge will be nill.
So even the premise of the experimental setup is flawed.

-Tim

It is all based on Albert Einstein's theory which you
can find here:
http://www.fourmilab.ch/etexts/einstein/specrel/www/

Kind regards,
Sue...