From: "Malcolm Watts"
Date: Sun, 25 Jul 2004 12:38:08 +1200
Subject: Re: [TSSP] Bang energy vs. streamer length measurements
Hi Marco,
Thanks for an interesting and infornmative set of
measurements. Apologies for not commenting before now (overwhelmed by
too many things). I do have a couple of comments to make which may or
may not be useful. You wrote:
>Several trials have indicated that 20 seconds between two bang
>sequences is sufficient to ensure statistical independence. On the
>other end, it has been easy to notice measurement correlation for a
>delay of 5 - 10 seconds.
That fits with a finding I made with one particular coil
configuration that increasing the "single-shot" frequency from about
1Hz to 2Hz almost doubled (somewhere around 80% I would say) the
distance that a leader connected to a grounded target i.e. the
distance was adjusted for each PRF to get something like a 90% hit
rate.
>Bang repetition can't do miracles if the bang energy is limited.
This observation makes it clear that for a classic SG configuration,
John Freau's Pwr vs sparklength formula defines a best-you-can-do
figure for some given power input. In other words, an increase in
power in the form of increased BPS beyond this lowers what one might
term the "efficiency" of the coil. It also appears that this ties in
with John's observation that bigger bangs at lower BPS will always do
better for a given power input, at least up to some minimum BPS.
>My personal opinion is that an increased bang frequency interacts
>with the accumulated space charge and "strightens" the leader path.
I think the observed "sword-like" sparks in interrupted CW operation
where many tens of cycles are allowed per break supports this
observation.
Malcolm
Maintainer Paul Nicholson, paul@abelian.demon.co.uk.