Re: Positive VS negative streamer

To: tesla-at-pupman-dot-com
Subject: Re: Positive VS negative streamer
From: "John H. Couture" <couturejh-at-worldnet.att-dot-net> (by way of Terry Fritz <terryf-at-verinet-dot-com>)
Date: Wed, 28 Oct 1998 11:00:55 -0700
Approved: terryf-at-verinet-dot-com

  All -

  Tesla said that the dominant polarity of the TC secondary terminal when
the Tesla coil is operating is negative. He said this is due to the the
dampened wave being off center with the negative peaks being greater. The
dampened wave has other idiosyncrasies. The peaks of this wave do not occur
at the same time as a sine wave of the same frequency.

  Some coilers have made these tests and said the polarity was positive.
However, when correctly made the tests indicate the polarity is negative.
You can verify the negative polarity by doing the the test I posted some
time ago. I believe the dominant streamer and space charge would be
negative when the secondary terminal is negative. 

Apparently it has been found that with a certain voltage impulse wave the
space charge is positive. But how does this apply to Tesla coils? 

  Terry - I visited your site and scope pics. I am always amazed that I can
print pics so easily that were made by someone else's scope. Thank you for
making my life so pleasant. The pics do show spikes and they are labeled
negative polarity! How would you match these spikes to any particular
secondary spark anyway? Are you saying that those random TC extra long
sparks are all positive?

 John Couture

------------------------------------

At 06:39 PM 10/25/98 -0700, you wrote:
>Original Poster: Terry Fritz <terryf-at-verinet-dot-com>
>
>At 05:29 PM 10/25/98, you wrote:
>>At 03:51 PM 10/24/98 -0600, you wrote:
>>>Original Poster: "B**2" <bensonbd-at-erols-dot-com> 
>>>
>>>Hi All,
>>>    Found the following information.  Seems to relate to recent
>measurements.
>>>
>>>Quote:
>>>
>>>"EXPERIMENTS CONDUCTED IN THE LABORATORY
>>>
>>>    To understand the basic mechanism by which the positive corona sheath
>>>is neutralized by the return stroke, we conducted the following experiments
>>>in the laboratory.  The potential of the central wire of a coaxial
>>>cylindrical system was raised to a very high level by applying a positive
>>>voltage impulse.  This pulse led to the generation of positive space charge
>>
>>-----------------  snip
>>
>>  It should be noted that the Tesla coil uses a high frequency dampened
>>sine wave not a voltage impulse. So how does this post apply to Tesla coil
>>operation?
>>
>>  John Couture 
>>
>>
>
>This is related to the spikes we see at the peaks of the streamer current
>waveforms.  These spikes are much more likely to appear in the positive
>polarity.  We think the spikes are little streamers darting out trying to
>form big streamers.  See the scope pics at:
>
>http://www.peakpeak-dot-com/~terryf/tesla/misc/spikes.jpg
>
>	Terry
>
>
>