RE How do sparks propagat

To: tesla-at-poodle.pupman-dot-com
Subject: RE How do sparks propagat
From: Tesla List <tesla-at-stic-dot-net>
Date: Thu, 08 May 1997 01:02:31 -0500
Approved: tesla-at-stic-dot-net
Subject:      RE How do sparks propagat
       Date:  Wed, 07 May 1997 15:26:07 GMT
       From:  robert.michaels-at-online.sme-dot-org (Robert Michaels)
Organization: Society of Manufacturing Engineers
         To:  tesla-at-pupman-dot-com


        Verrrry interesting.  What was the =wavelength= of the eximer
        laser?   (Short-wave uv light can certainly ionize air)

        Also, how much did the photoelectric effect contribute to
        the results?

                No less a personage than Einstein himself showed
                that if an electrode is illuminated a discharge
                will more readily take place from it than if that
                same electrode is in darkness.


T>robert.michaels wrote:

T>[snip]
T>>         You may be referring to the use of =focused= beam from a
T>>         =pulsed= and very powerful =Q-Switched= laser.  Such can
cause a
T>>         minute and instantaneous plasma in open air at the point
T>>         of focus.
T>>
T>>         This is a horse of a very different color from establishing
T>>         a =lengthy= conductive path thru air along which a Tesla
T>>         discharge may be guided - by the use of a laser or microwave
=beam=

T>Related trivia:
T>In 1992, a Japanese research group actually succeeded in initiating an
T>electrical ionization path thru the air using an excimer laser.  The
T>test
T>setup consisted of two elevated terminals (HV and Gnd), spaced about 3
T>meters
T>apart, attached to a 500kV impulse generator. The output beam from an
T>excimer
T>laser was fired across the 3m gap, tangent to both electrodes.  The
T>photo
T>shows a nice bright discharge travelling along the light beam.  The
T>group
T>hopes to eventually use this technique to divert lightning strikes
away
T>from critical installations.
 [ ... ]

                         - - - - - - -

 [ ... ]

T>Given the large number of newbies on this list, I would like to
re-visit
T>an
T>old issue from a 'theory of arc dynamics' standpoint -- Why do many
T>coilers
T>report that a larger toroid increases the striking distance of their
T>coils,
T>given that increasing Coutput always decreases the output voltage?
T>(I am assuming that the striking range is increased by more than just
T>the
T>increase in toroid radius.)

T>-GL

        It's an interesting (if not fascinating) question.  I could
        advance a bunch of half-baked theories but nothing really
        cogent.

        The use of a larger toroid reduces the resonant frequency
        of the system.   Lower frequencies seem to be associated
        with greater spark length -- maybe this has something to do
        with it.

                                        Puzzled in -- Detroit, USA


                                        Robert Michaels