Horace wrote: > You [WB] wrote: "- if I tap upon the HV wire with a finger, the furrow in > the mist jerks after a short delay, maybe .05sec for 13cm, that's > five MPH (can't visualize KPH)".
This made me think that if we find a way to measure more accurately the delay, and therefore the velocity of a hypothetical carrier responsible for this delay, then we can determine the carrier's mobility by dividing the velocity by the average e-field strength (voltage/distance). If we find something close to the mobility of air ions (2*10^-4 m/s per V/m), then air ions are probably responsible for the delay. If we find a much lower mobility then it's something else. As an example of such a computation, pretending WB's rough figures above are accurate, and assuming a 10kV voltage, the velocity would be 13*10^-2/(5*10^-2) = 2.6 m/s, the average field strength would be 10*10^3/(13*10^-2)= 77*10^3 V/m, so the mobility would be 2.6/77*10^3 = 3.4*10^-5 m/s per V/m which would be ~ 6 times less mobile than air ions. Michel ----- Original Message ----- From: "Horace Heffner" <[EMAIL PROTECTED]> To: <[email protected]> Sent: Tuesday, June 05, 2007 11:19 PM Subject: Re: [Vo]:ion currents in pingpong balls > > On Jun 5, 2007, at 12:02 PM, William Beaty wrote: > >> >> It is possible that all these phenomena are created by >> Electrospray, where >> a droplet clinging to a charged surface begins emitting a series of >> microscopic charged droplets. An older form of ink-jet printer >> was based >> on this type of electrostatic droplet-series emission. > > > You wrote: "- if I tap upon the HV wire with a finger, the furrow in > the mist jerks after a short delay, maybe .05sec for 13cm, that's > five MPH (can't visualize KPH)". That's a sign the thread maintains > *tension*, which would not be possible if it were a string of like > charged drops. HV jet drops move much faster than 5 MPH, and can not > sustain beam continuity over long distances, yet: "Occasionally I see > a very "powerful" ion-thread, one which can extend itself more than > 2ft ...". > > More convincing: "- When I used a soda straw and blew upon a thread > with all my might, the dot in the mist only moved a little. The 5mm > dot was changed to a 10mm x 30mm blotch. INCREDIBLY BIZARRE! The air > blast either causes the thread to spread out into a narrow fan, or it > causes it to vibrate at high speed so that the thread tip traces out > an oblong blotch in the mist. These threads are robust! Not at all > like smoke, they are more like carbon-fiber spiderwebs under high > linear tension. " > > Doesn't sound like charged ink-jet drops to me: "I've seen two > threads with 5mm spacing between them, yet they were 15cm long. If > they were highly charged, they would repel apart .... - I've seen > pairs of threads come from a fingernail top, extend down about 10cm > and apparantly follow the field lines, all the while maintaining a > distance from each other of about 1cm! They don't seem to repel each > other much." > > Regards, > > Horace Heffner >
