Re: volume polarization vs. surface charge

[Bob Sciamanda <trebor@VELOCITY.NET>]

> The surface charge due to polarization of a dielectric is, whether you
> consider it "real" or "virtual", not capable of constituting the charge
> which makes the spark when the capacitor discharges. It isn't
> macroscopically mobile.


But the field of such "bound" charges can drive currents in nearby
conductors, ionize air, etc.  The field produced by a polarized (and
neutral) dielectric is very real; it is the field of a dipole distribution,
calculable from an "equivalent" bound monopole charge distribution.

Consider the practical applications of the momentary EMF achieved by sharply
stressing a piezoelectric substance (eg in barbecue ignitors, etc.).

Bob Sciamanda
Physics, Edinboro Univ of PA (ret)
trebor@velocity.net
http://www.velocity.net/~trebor