RE: (Fwd) RE: Longitudinal Waves

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Malcolm Watts by way of Terry Fritz <twftesla-at-qwest-dot-net>" <m.j.watts-at-massey.ac.nz>

Hi David,
          To get to one point........
On 12 Feb 2002, at 18:56, Tesla list wrote:

> Original poster: "David Thomson by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <dave-at-volantis-dot-org>
<snip>

> >> Longitudinal waves do not propagate in the same manner as transverse
> waves.
> >> Transverse waves are voltage waves.  There are two voltage waves in every
> >> transverse wave, each of opposite polarity from the other.  If left to
> >> themselves, these waves will eventually attract each other and damp
> >> themselves out.  And even when the two waves cancel out, the longitudinal
> >> component of the wave is still there.
> 
> >Forgive me for saying so but that sounds a bit dubious to me. I've never
> heard of waves attracting each other. And what happens to the energy that
> was in them following cancellation?
> 
> I realize you may not have heard of this before.  And I don't want you to
> accept this on faith.  Do some research on the true nature of a sine wave.
> You will find that the sine wave being measured on an oscilloscope has a
> greater positive component than it does a negative component.  The
> oscilloscope compensates for this unevenness by using artificial means.  An
> oscilloscope only measures one of the voltage waves and to make it look good
> to the engineer, the electronics have been modified to make it appear as
> there were only one perfect wave.  After all, both waves are mirrors of each
> other, but have opposite polarities, so for most electronics purposes one
> average wave suits the engineer well.

Having spent half a lifetime repairing oscilloscopes as well as 
calibrating them I must strongly disagree with the statements in that 
paragraph. Bear in mind that you can invert one channel of most if 
not all scopes. The fact that there is no DC shift in a pure 
sinusoidal waveform when you do that speaks volumes. 
 
> What happens to the energy is what I have been trying so painstakingly to
> get across.  There are two vectors in any wave.  There is the voltage vector
> and there is the longitudinal vector.  The voltage vector is actually two
> electrostatic charges traveling opposite to each other.  When the two
> voltage vectors have cancelled each other out, the longitudinal vector
> remains and suffers no loss until the wave is absorbed by another field or
> mass.  Also, if I were more advanced in math, I would check to see if energy
> being expended in canceling the voltage is not being transferred into the
> longitudinal component.  Either the two waves cancel thus produce heat, or
> they cancel by transferring the energy toward the longitudinal component of
> the pulse wave.
> 
> BTW, the two opposing fields of voltage are just like the two opposing
> gravity waves produced in a pulse wave on the surface of water.  If you drop
> a stone into a pond, the stone acts as the sudden release of potential that
> starts the wave.  To make the pond example look like your oscilloscope view,
> we will take a plane perpendicular to the water surface that intersects the
> vertex formed by the stone.  What the water surface outlines is a damped
> wave and illustrates water pressure as opposed to the electrical pressure of
> voltage.  Opposite to this visible water pressure wave is an invisible, but
> real gravitational pressure wave relative to the mean surface of the pond.
> The mass of the water under the positive portion of the wave is greater than
> the mass of the water under the negative portion of the wave. The gravity
> works more to pull against the wave's high pressure and works less at
> pulling on the wave's low pressure and the two waves cancel each other.
> Gravity therefore behaves as an "electrostatic" force that neutralizes water
> pressure waves just as there is an electrostatic force that neutralizes
> voltage pressure waves.

I must dispute that too. If the medium and its interaction with its  
boundary is lossless, waves will perpetuate. A pool bounded by a 
smooth rockface makes a pretty good energy bottle. I've seen it on 
plenty of canoe trips.
 
> To further the analogy of the stone in the pond and an electric pulse, a
> stone falling into the water not only creates a transverse pressure wave,
> but it also displaces water longitudinally that generates a sound wave.  The
> sound wave can still be heard by sensitive instruments even though the
> surface wave has been damped.  To go the other way with the analogy of water
> and electricity, the US Navy broadcasts sound waves through the ocean that
> cause severe damage in aquatic animals but produce no corresponding
> transverse waves on the surface.  In areas where longitudinal pulses are
> generated by land based installations for communicating with submarines and
> locating underground structures, there are no corresponding disturbances on
> the radio receiver for the given frequency, but people complain about health
> effects and noises that are perceived within the body.
> 
> Tesla coils are pulse generators.  We can design and tune these pulse
> generators to produce pulses with high voltages, high frequencies, or low
> voltages, high frequencies.  And the longitudinal component can be of high
> current, high frequency, or low current, high frequency.  The longitudinal
> component can also have a strong or weak magnetic component as well.  I can
> see how the longitudinal component of the wave looks metaphysical to an
> engineer, but it is there.  We accept that a photon has no mass and yet
> carries energy across the Universe; this sounds metaphysical too, but we
> incorporate it into our science anyway.  No matter how we slice it, though,
> the longitudinal component is always a function of time; just as the speed
> of light is.  We can design the Tesla coil with complete independence
> between transverse and longitudinal components.  A lot of work has gone into
> developing the transverse component of the pulse wave in Tesla coils.  Now
> I'm going to look into the longitudinal component and see what I can find.
> 
> >A standard 1/4 wave resonator is such a chamber.
> 
> Yes, and it is usually designed to maximize the voltage at the terminal.  We
> get so enthralled at those beautiful long sparks that we overlook the
> longitudinal waves.  And for most people, this is great.  The sparks are
> entertaining enough.

The point is, energy can be bottled up in it, sparks can be prevented 
from issuing and just the circuit losses will convert the oscillating 
energy to heat. The higher the Q, the longer the oscillations 
persist. And Q's in some types of resonator can be made very high 
indeed.
 
> >I'm sure that winding a flat spiral can't be all that difficult, even with
> rather fine wire ;) I'll sit back and listen to what other list members have
> to say for awhile before deciding whether it will be worth the effort.
> 
> Thanks for your engaging discussion.  When I have to find words to express
> my ideas, I come to understand by ideas much better.  Hopefully, even if you
> still choose to disagree, you will at least understand what I'm trying to
> convey.

Personally I am waiting for unequivocal confirmation that you are 
doing what you say you are, nothing more.

Regards,
malcolm