Basically, the question that you are asking is if Maxwell's
Equations are a correct description of the way electromagnetic fields
behave. If you agree that you have a time-varying electric field between
the plates, and you agree that Maxwell's Equations give a correct
description of the fields, then you reach the conclusion that you have to
generate a magnetic field that also is time-varying. If you are willing
to do the calculation for a simple case (a parallel plate capacitor with
circular plates) it is not hard to show that you generate lines of the
B-field that are circular, and that the amplitude of the B-field decreases
linearly with distance from the axis of the capacitor at any instant of
time. That's the condition you need for radiation!
Mark
Dr. Mark H. Shapiro
Physics Department
California State University, Fullerton
P.O. Box 6866
Fullerton, California 92834-6866