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Re: Ball lightning
>>From gowin-at-epic-1.nwscc.sea06.navy.milWed Nov 6 21:30:21 1996
>Date: Wed, 06 Nov 1996 13:18:19 -0500
>From: Dan Gowin <gowin-at-epic-1.nwscc.sea06.navy.mil>
>To: tesla-at-pupman-dot-com
>Subject: Ball lightning
>Bert,
> Correction on that grid dipping of both coils together.
>Thats 120 KHZ resonate freq., My alligator clip was not attached
>correctly. In which case I was way out of tune.
> I would like to postulate a theory though. Could it be
>possible that some sort of harmonic focussed itself within the area
>between the two coils. This type of RF pocket is very common in
>Microwave systems.
> For example if an individual did water boiling experiments on
>a microwave oven with a non rotating tray. You would find that some
>parts of the oven heat and some don't. This happens to be one of the
>reasons for rotating trays in low wattage microwave ovens. I've also
>seen this effect on the optical side. Sometimes Argon lasers mode
>selection prisms will shatter due to IR harmonics focussing within
>this device.
> With the understanding that a Tesla coil is indeed very much
>like a lazing system. That in fact the propagation wave dose in fact
>oscollate back and forth through the coil and build until breakout.
>This line of thought might be in fact correct since I know the Japanese
>are in fact creating ball lightning with microwaves systems. Hmmmm,
>maybe some plasma modeling is in order hear.
>
>D. Gowin
Dan,
The phenomenon to which you refer in the microwave oven which causes
hot and cold zones in space is called standing waves. This is when
the incoming energy from the waveguide port into the oven enters the
oven cavity and starts reflecting around inside. At points the
reflections will be in phase with the incoming energy and hot spots
will occur. At other places there will be a merging of waves 180
electrical degrees apart at the same amplitude. Phase cancellation
and a cold spot occurs. The wavelength of the energy here is very short.
Just 12.24 cm. (2450 MHz). Hot spots can occur that follow a three
dimensional gaussian bell curve distribution which are 1/2 of this
dimension (6 centimeters or 2.36 inches) in size.
At Tesla coil frequencies, say 100 kHz, the wavelength is 3000 meters
long! Any phase reinforcement occuring in free space due to
standing waves at this fundamental frequency will create a hot zone with a
dimension of a half wavelength or 1500 meters (5000 feet). Let us look at the
energy of a Tesla coil distributed over a linear distance of such a large
dimension in another way to better grasp the conept of space dilution at work
here. Lets say we have a rather enormous Tesla coil and it is capable
of outputting 10 kilowatts of RMS averaged power. Let us simulate
that with a DC power supply that can deliver 10 kilowatts into a
resistance load. Now, instead of an electromagnetic standing wave in air
5000 feet long, let's use a piece of nichrome resistance wire 5000
feet long. 10,000 watts divided by 5000 feet equals two watts per
foot. I would not hesitate to touch this wire with my bare hand.
Consider now that the average rotary, pole pig powered TC can
probably deliver just several hundred watts of RMS averaged power off the
top, not 10 kilowatts. That kind of power in a standing wave spread over 5000
feet is not going to be very effective in melting snow, let alone
metal aligator clip terminals.
Consider also that most of the energy occurs at the fundamental frequency.
By the time you are at the tenth harmonic of the fundamental your
energy level would be barely detectable. Let's say for pulling a
number out of my hat that we are 20 db down at the 10th harmonic.
Then we have just 1/100th of our several hundred watts. So we have
maybe three watts forming a phase additive 'hot spot' with a half
wavelength dimension spread over 500 feet (1/10th the wavelength of
the fundamental). I wouldn't be afraid of putting my bare hand in there either.
I think your explanation for vaporizing the wire and alligator clip
must be found elsewhere than standing waves, and or harmonics.
Is it possible that you merely melted the wire explosively by virtue
of extremely high current and simple resistance heating? The base
current in a Tesla resonator can be quite high.
rwstephens