Maxwell Equations

I have a simple unique question: Why in the homogeneous Maxwell
Equations the E- and B-Field are used and in the inhomogeneous ME the
D- and H-Field are used? Please give me an answer as soon as possible!

Melo wrote:


The E and B fields are force fields. They describe the energy-momentum
change d(p_0, vec p) of particle of charge q along its path in a given
field environment build up by all other charges and currents execept
that of the test particle

dp_0 = q E . dx
d\vec p = q (E dt + dx\times B )

In contradistinction the fields D and B are the local expressions of the
field generating charge and current distributions. They are easily
understood as jumps of thin charge and current distibutions in a plane

(D_right- D_left) A s/m^2 = charge density for a charged metal plane in
xz-plane

(H_right- H_left) A/m for current density in y-direction

The material equations E = 1/eps D, B = mu H are a consequence of the
Lorentzinvariance: They hold the velocity of light and its invariance
wrt group of Lorentz transformations of fields and spce time coordinates.

All in one: H,D take up momentum of a source, E,B deliver momentum at
the target. But in the real world this distinction is a bit
oversimplified, neglegting the back reaction.

--

Roland Franzius