Hi Horace, Let's try to agree on simple things, in a simple example. Say at t=0 the HV is turned on instantly and the +ve anode's tip starts emitting a dotted line of slow-flying +ve ions which won't arrive before t=50ms. Say the flow of charge is a constant 10nA flowing out of the tip. The anode current waveform is therefore a step function, zero for t<0, 10nA for t>=0. What I am saying is that the cathode current is exactly the same step function, as it would be for any electronic component, without a delay corresponding to the flight time, i.e. cathode current won't wait for 50ms to turn on. Do you agree with this?
Regards, Michel ----- Original Message ----- From: "Horace Heffner" <[EMAIL PROTECTED]> To: <vortex-l@eskimo.com> Sent: Wednesday, June 06, 2007 7:09 PM Subject: Re: [Vo]:Filament ion jets > > On Jun 6, 2007, at 5:01 AM, Michel Jullian wrote: > >> Hi Horace, >> >> Sorry for the empty reply, my finger slipped. >> >>>> There will be no such delay, that was my point, except of course >>>> the subnanosecond speed of light delay for Coulomb forces to act >>>> across a few tens of cm, even if it takes 50 milliseconds for the >>>> "whatever" to cross the gap so that one might expect 50 >>>> milliseconds or more would elapse before current comes out the >>>> bottom of the pan. >> >>> But that was *my* point. If threads are in place, there is a >>> conductor across the gap, thus the signal should travel fast across >>> the gap, not having to wait for insulated drops to carry the signal. >> >> This is not the point I was making. The point I was making was on >> the contrary that even if the current is carried by slow drops or >> ions or whatever which take ages (milliseconds) to cross the gap, >> the signal will still cross at the speed of light (subnanosecond). >> Let me know if what I wrote previously makes sense in this light, >> otherwise I can explain. > > > I think your statement makes sense in this context if you assume the > air gap plus drops, acting as a capacitor, conducts a signal similar > in orders of magnitude to what we would expect from a filament. > > My underlying assumption is if there are no filaments there will be > no signal - not at the 10 nanoamp level measured by Bill Beaty > anyway, no signal until a filament contact is "made". The fact the > air gap is a capacitor seems to me irrelevant because the capacitance > is miniscule, so it appears we have differing underlying assumptions > in that respect that prevent us from mutually making sense of this. > > It appears we both agree and assume the signal should travel fast > across a filament, i.e. not at the filament molecule speed. It was > about this I said: "But that was *my* point." We also both agree the > signal would travel fast across an air gap capacitor, but apparently > we have highly differing assumptions about the ability of the air gap > capacitor to conduct a signal, or at least the comparative magnitude > of strength of signal from an air gap vs a filament. > > I suspect we are not communicating at all and have not made sense > about the nature of the signal onset though. If a continuous signal > actually is detectable and carried by the capacitance of the drops > plus air in the gap, then its onset, the rise in its magnitude, > should be slow. The onset of a (continuous) signal carried by a > filament should be very fast - at the moment of "make", and > disconnect fast, at the moment of "break". > > If there are filaments making a connection then the signal travels > according to the transmission line characteristics of the filament, > which may well not be light speed, but will still be fairly fast, sub- > nanosecond I would expect. I expect there may be some surprises in > this regard, at differing frequencies and rise times, related to the > mass of the probable charge carrier in a filament, the proton. > > A signal carried only by the differing potentials of independent > drops would take millisecond delays, dependent on the drop velocity, > and I think we agree on that, have made sense of that. A single > filament's signal onset when a "make" occurs would be very fast, not > dependent on the stream velocity. If in fact the signal were carried > capacitively through independent drops in the gap, where the gap plus > drops act as a capacitor, then the signal onset (of a continuous > signal) would be comparatively slow, because the strength of signal > depends on the capacitance of the gap, thus the geometry of the gap > and the speed of filling the gap with droplets. > > The above may seem trivial, but I think the distinction is critical. > For example, given two adjacent target plates, and slowly moving a > source needle from above one to above the other, we would see a > (superimposed continuous AC) signal jump from one plate to the other > very fast if a filament were involved, and gradually switch between > the two plates if capacitive transmission were involved. If lots of > filaments from the source electrode were involved, we should still > see the change in signal amplitude occur in jumps, while if > capacitive conduction is occurring then the transition of signal > strengths would be continuous. > > Regards, > > Horace Heffner >
