Re: E&M Revolution

[John Mallinckrodt <ajmallinckro@CSUPomona.Edu>]

[I sent this a couple of days ago and I don't believe it showed up on the
list.  Here's a second try.  JM]

Except for the unconventional choice of direction for polarization, this
system is reminiscent of the Heaviside-Lorentz unit system which shares
the simple constitutive relationships between D,E, and P and B,H, and M.
The Heaviside-Lorentz system goes a worthwhile step further, however, by
setting epsilon_o = mu_o = 1.  As a result the only dimensioned constant
that rears its ugly head anywhere is c.  The equations of E&M are
particularly beautiful and particularly out of touch with practical
electronics in this system. 

There are lots of other well-known unit systems for E&M, each of which has
its own particular advantages.  Frankly, I liked the one David Bowman
proposed here a while back.  At any rate, before you go inventing yet
another new wheel, you might want to look at the appendix on units and
dimensions in Jackson.

John

On Mon, 1 Dec 1997, Timothy J Folkerts wrote:

> I would like to modestly propose a revolution in E&M 
> nominclature.  (Note:  e0 = epsilon naught, mu0 = mu naught)
>
> Let the electric dipole moment be p = qd, but point FROM + TO -.
>      (change the sign)
> Let polarization be P = (p/V) / e0
>      (add the 1/e0)
> Let D be given by (Del dot D) = rho(free) / e0
>      (add the e0)
>
>
> Let magnetization be M = (m/V) * mu0
>      (add the mu0)
>
> Let H be given by Del x H = J(free) * mu0
>      (add the mu0)
>
>
> THE ADVANTAGES
>
> The fundamental fields (E & B) are unchanged.
>
> The pesky e0 and mu0 are eliminated from the equations relating E,D,&M; 
> and B,M,&H.     
>      B = H + M
>      E = D + P
>
> The equation for E is brought in line with the more logical equation 
> for B: the fundamental field (E or B) is the *SUM* of the free field (D 
> or H) and the bound field (P or M). 
>
> All the fields have the same dimension (much like cgs).
>
>
> THE DISADVANTAGES:
>
> The only thing I can think of is retraining the current generation of 
> physicists, rewriting textbooks and retabulating handbooks.
>
> Just minor stuff like that ;)
>
>
> So, any comments from the gallery???  Is this worth an AJP article or 
> has it already been done?

-----------------------------------------------------------------
 A. John Mallinckrodt      http://www.intranet.csupomona.edu/~ajm
 Professor of Physics    mailto:ajmallinckro@csupomona.edu
 Physics Department       voice:909-869-4054
 Cal Poly Pomona            fax:909-869-5090
 Pomona, CA 91768-4031   office:Building 8, Room 223