From: "Terrell W. Fritz"
Date: Fri, 25 May 2001 15:41:12 -0600
Subject: Re: [TSSP] Genetic optimisation
Hi Boris, I remember Marco's coil as having a power supply problem that may have affected this: http://www.pupman.com/listarchives/2000/November/msg00117.html I forget the details but that may have affected his toroid breaking out at that time. Marco's system is very good for this since his is so well controlled. I have his system running now so I'll report back. I may have to use a fairly large grid size and adjust things to get good resolution at the toroid surface... Catching up on mail now ;-)) Cheers, Terry At 11:50 AM 5/23/2001 -0700, you wrote: > >Hi Paul,All, > >> Looks like 26kV/cm is the figure to work with at >> normal TC frequencies, >> - comes as some relief that the value is not >> severely frequency >> dependent, things would be tricky if so! >--- >Surely,~26-28KV/cm critical surface field would be all >right to assume for TC freqs (and standard >atm.conditions) >Definitely,if such field appears for a certain time >,it will get show to start happening per see. >But,what counts the most here is one thing:TIME... >By this I don't mean just time of TC waveform >exceeding this treshold ,but also time pauses between >2 primary condensers bangs-->in other words some >depedence on BPS (belive it or not!). >John Freau experiments with smooth toroids are very >valuable when we speak of this matter. >He has noticed smaller bang size (innital cap energy) >needed for visual spark breakout with higher BPS rate >than with lower BPS rate. >Few months ago,I contacted with M.Denicolai and he >said he would make controled experiments on his thor >in order to investigate such phenomenon this summer . > >Something else you should know as well.With about 400 >KV peak voltage on his coil Marco was unable to get >breakout of his 20*150 cm smooth toroid. >Only with Ep~10 J he started to observe first faint >streamers coming from the terminal. >Question improved E-Tesla program should answer to: >What max. toroid surface field corresponds to 400 KV >voltage on THOR secondary? >---- > > >> >> If I've understood things right, the leader >> formation begins and >> continues as long as this gradient can be maintained >> just ahead of the >> leader. I guess the significant threshold involves >> meeting this value at >> the surface of the smooth toroid and once a leader >> begins to form, its >> sharp point will then ensure that the leader forms >> rapidly for quite >> some distance - even though the 'background' field >> from the >> topload would, by itself, fall below the 26kV/cm >> threshold only a little >> way from the surface. Subject to the toroid having >> enough charge >> available to support that formation. What stops the >> leader formation? >> I guess either it hits earth or it runs out of >> charge - the toroid is >> depleted and the 26kV/cm cannot be maintained at the >> tip? So a big >> toroid would be reluctant to break out (modest >> surface gradient), but >> it would throw a long streamer as soon as it did >> (lots of charge >> available)? >> >> I'm afraid I've got some more questions! >> >> > A long spark (>6 cm) is characterized by multiple >> avalanches in an >> > evolutionary sequence: streamer flash(es) --> >> leader propagation >> > (fed by groups of streamers) --> spark (if leader >> > bridges the gap). >> >> Can we assume that this whole sequence takes place >> in a timescale short >> compared with an RF cycle - I suppose thats so >> because if not there >> would be a bigger frequency dependence? >--- >I think we can,althought some scopings on 250 Khz+ >coils I saw in past ,displayed not so small >differences. >--- > >> >> When the HT falls away, do things recombine and >> settle down sufficiently >> that on the next half cycle there is no 'memory' of >> the previous half >> cycle? >> >> Ultimately what I'm fishing around for is some >> confidence that some >> acceptable and realistic account can be taken of the >> breakout >> thresholds, otherwise attempts at non-linear time >> domain modeling will >> founder on that point. I feel as though we are on >> top of the technical >> matter of computing the response and now, quite >> suddenly it seems, we >> are up against this more difficult problem of >> finding a load conductance >> function which provides an acceptable summary >> description of the >> breakout dynamics. >> >> If I've got things right, then Terry should be able >> to calculate quite >> easily the top voltage at which streamers should >> suddenly start to form, >> and we might also be able to calculate an estimate >> of streamer length >> too (as a function of topvolts). Given those two >> separate figures (or >> functions) we would then have the choice of >> optimising for max topvolts >> or max streamer length, using the same genetic >> software but with two >> different merit functions. >> >> Cheers, >> -- >> Paul Nicholson, >> Manchester, UK. >> -- > >Regards, >boris > >__________________________________________________ >Do You Yahoo!? >Yahoo! Auctions - buy the things you want at great prices >http://auctions.yahoo.com/
Maintainer Paul Nicholson, paul@abelian.demon.co.uk.