From: Bert Hickman
Date: Sat, 02 Nov 2002 13:31:48 -0600
Subject: Re: [TSSP] Top Voltage
Hi Boris and all,
Sorry for the delayed responses. I've just downloaded a large number of
papers on gas breakdown and have just begun the process of reviewing
them. Between delayed breakout and space charge effects, there may
indeed be some reasonable explanations for the significantly higher
breakout voltages that Terry is measuring. However, I need to do more
digging before sharing any of this with the list. It's not likely that
there are significant magnetic field effects here - I agree with your
assessment that the H fields are simply not strong enough.
Streamer and leader propagation should occur only as the top terminal
has an increasing potential - i.e., during ringup - and not during
ringdown. If we haven't seen evidence of breakout during a given
ring-up, we'll likely not see any evidence of breakout during the the
subsequent ring-down. If we generated corona or corona streamers, we've
injected space charge into the region near the terminal. If the terminal
polarity is rapidly reversed (before the excess space charge can diffuse
toward neutrality), the terminal breakout voltage should be lower when
the terminal swings to the opposite polarity. I think... :^)
Best regards,
-- Bert --
--
Bert Hickman
Stoneridge Engineering
"Electromagically" (TM) Shrunken Coins!
http://www.teslamania.com
boris petkovic wrote:
> Bert Hickman wrote:
>
>
>>Part of the problem is the relatively large
>>dynamic range and
>>the statistical character of the phenomena.
>
> ---
> About large dynamic range part I agree.For breakout
> observations,like Paul said,there were no signifacant
> standard deviations involved.Problem was and is
> significantly higher breakout threshold where Terry
> starts to see streamer-arcs breakouts from the sphere
> when it was placed higher.
> Visible corona threshold (from formula I saw and
> posted) would be about 40 kv/cm.In lower position,
> software reports 42 kv/cm for corresponding observed
> breakout potential which is in good agreement.But for
> higher sphere position report was about 55 kv/cm.
> Between 55 and 40 kv/cm with Q=94 there is cca 9
> cycles of 38 kHz,between 55 and 30 kv/cm cca 19.
> IMO something very interesting should be happening
> during that time from physical point of view to
> preserve streamer formation.I haven't gave a thought
> to magnetic field effects yet becouse I think they are
> irrelevant (to weak) to be cause for such behaviour.If
> we can trust sofware for higher placed sphere field
> prediction,puzzle must be in a weak discharge
> interaction with different field configuration.
> ---
> Peak currents associated with
>
>>streamers and leaders may
>>be a million times larger, so instrumenting to
>>detect/measure both may
>>be a challenge. Perhaps small corona currents can be
>>indirectly detected
>>via subtle changes in secondary Q combined with
>>secondary base charge
>>changes?? Tough problem...
>
> ---
> The only problem here is requirement for
> instrumentation for high precision measurment.
> Once you measure Q&Fr with low energy imput ,next
> times with higher and higher energy inputs but always
> below visible breakout threshold.
>
> regards ,
> Boris
>
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Maintainer Paul Nicholson, paul@abelian.demon.co.uk.