Bart Rowlett wrote:

Hi Bart. Good post, and good to see you here again.

The electric field is vector field, characterized as having a field
strength in volts per meter dependant on spatial location, direction,
and perhaps time.

I don't understand what the term 'E-field voltage drop' could mean. Same
with 'H-field current drop'.

I think I understand what you both are saying. In the case of a
standing wave, the 'current drop' Cecil refers to (as I understand it)
is simply the current differential between two positions
Iz2 - Iz1, where I(z)=Imax(cos(wt + phi(z)), the amplitude of the
standing wave current as a function of position z. Phi being the kind
of phase which for a traveling wave varies with time at a given point,
and in this case varies with position along the standing wave. The
distinction being that Phi is not the phase of current with respect to
voltage.

The other point of disconnect between the parties hereabouts relates to
the occasional lack of distinction between the 'flow' of electrons, and
the propagational 'flow' of an EM wave.

73, Jim AC6XG

Likewise, saying that the H-field current flows and
the E-field voltage doesn't flow is nonsense.


H-field current flows?

The field H (amps per meter), is the so called magnemotive field. It
doesn't flow anymore than voltage flows through a resistor, and is
associated with the generation of magnetic flux. The magnetic flux
density, B, has the units of webers per meter squared and can be
integrated over an arbitrary surface to evaluate the total magnetic flux
passing through that surface. Magnetic flux is somewhat analogous to
current but H is not at all.

The E-field and H-field

are usually inseparable.


In the classical electromagnetic model, E & H are completely separable.
They are coupled via Faraday's law, and Maxwell's so called
displacement current. At steady state (DC) no coupling exists. When
one field quantity _varies_ in time, so will the other in accordance
with the curl equations. The coupling described by the time varying
part of the curl equations only involves the time varying components.

When determining the analysis method used to gather insight into a
physical system, one of the first considerations is to determine if the
time varying field components need to be considered, and if so, which
ones. For example, analysis of a 60 Hz power supply choke, or electric
motor, usually ignores the electric field in the air gap arising from
the time varying magnetic flux density. It's not important in the gap,
but is the driver of undesirable eddy currents in the core laminations.

bart
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