Ground, water, and fields

Greetings,

A recent newsgroup discussion brought up a question I'd like to explore
further. Perhaps someone on this list could provide some insight.

At DC, water is quite non-conductive and has a high dielectric constant. At
RF, it's lossy, so can be characterized as having non-zero conductivity as
well as a high dielectric constant. At least in the case of pure water, the
conductivity is determined by mechanisms other than those causing ordinary
DC resistance. Because of the mechanism by which the loss occurs, it
doesn't seem unreasonable to think that the apparent conductivity might be
different when interacting with magnetic and electric fields -- perhaps
very different. That is, if we calculate an apparent conductivity for water
based on its interaction with a magnetic field, then do the same based on
its interaction with an electric field, would we get substantially
different values?

If this is the case, a single set of conductivity and dielectric constant
values might not be adequate for NEC ground specification, but some sort of
field-sensitive value might be required instead. Of course, ground water
contains dissolved salts and so has non-zero DC conductivity, which may (or
may not) dominate and swamp any field-sensitive effects.

Would anyone care to comment on this?

Thanks,

Roy Lewallen
Received on Tue Oct 15 1996 - 15:57:28 EDT