115 research outputs found
Why the controversy over displacement currents never ends?
Displacement current is the last piece of the puzzle of electromagnetic
theory. Its existence implies that electromagnetic disturbance can propagate at
the speed of light and finally it led to the discovery of Hertzian waves. On
the other hand, since magnetic fields can be calculated only with conduction
currents using Biot-Savart's law, a popular belief that displacement current
does not produce magnetic fields has started to circulate. But some people
think if this is correct, what is the displacement current introduced for. The
controversy over the meaning of displacement currents has been going on for
more than hundred years. Such confusion is caused by forgetting the fact that
in the case of non-stationary currents, neither magnetic fields created by
conduction currents nor those created by displacement currents can be defined.
It is also forgotten that the effect of displacement current is automatically
incorporated in the magnetic field calculated by Biot-Savart's law. In this
paper, mainly with the help of Helmholtz decomposition, we would like to
clarify the confusion surrounding displacement currents and provide an
opportunity to end the long standing controversy
Observation of modulation instability in a nonlinear magnetoinductive waveguide
We report numerical and experimental investigations into modulation
instability in a nonlinear magnetoinductive waveguide. By numerical simulation
we find that modulation instability occurs in an electrical circuit model of a
magnetoinductive waveguide with third-order nonlinearity. We fabricate the
nonlinear magnetoinductive waveguide for microwaves using varactor-loaded
split-ring resonators and observe the generation of modulation instability in
the waveguide. The condition for generating modulation instability in the
experiment roughly agrees with that in the numerical analysis.Comment: 7 pages, 11 figure
- …