Oops I realize I haven't explained _why_ those glows occur, sorry. This is because the electric field between objects at different voltages (= voltage difference over distance for infinite flat plates) is geometrically enhanced near sharp tips or thin wires (low radius of curvature places), so this is where the field first exceeds the 30kV/cm air breakdown field when the voltage difference rises, causing air to become ionized and thus glowing. This glow extends from the tip or wire to a distance where the field gets below 30kV/cm.
Michel ----- Original Message ----- From: "Michel Jullian" <[EMAIL PROTECTED]> To: <[email protected]> Sent: Saturday, August 04, 2007 4:32 PM Subject: [Vo]:Re: Electron fugacity, deuteron fugacity, and applied fields Hi Richard, I don't know about ion exchange resins but St Elmo's fire on cattle horns or any grounded tip pointing towards a high voltage cloud makes total sense, it's the well know phenomenon of corona discharge many times discussed here, first observed historically at the tip of ship masts: sailors observed a corona (crown) shaped glow around the top of the mast when a storm was coming --thus shaped I imagine because of highest field enhancement at the circular edge of the mast, or maybe it's just that they couldn't see the top central part of the glow whose view from the deck was impeded by the mast itself? Of course such gentle discharges between the clouds and the Earth sometimes evolve into heftier discharges :-) Michel ----- Original Message ----- From: "R.C.Macaulay" <[EMAIL PROTECTED]> To: <[email protected]> Sent: Saturday, August 04, 2007 2:51 PM Subject: Re: [Vo]:Re: Electron fugacity, deuteron fugacity, and applied fields > Horace wrote.. > > I think more talking is the way to go for now. At least it is > inexpensive, and it might save a lot of time and money. I might be a > bit slow to respond though. > > Howdy Horace, > > Keep talking. Stimulates others. Ion exchange resins used in water softening > perform in opposite from an understanding of electrical charge.. when you > think about it.. What causes the resin bead to release the buildup of > minerals attached.. salt. > Hmmm.. but why ? salt, NACL should cause a "binding agent" not a "releasing > agent". Another one of those anomalies of science where its right, you're > wrong. > Now take a longhorn bull with a full rackof horns, put the critter in a > pasture with lotsa cows out around the Llano Estacado country where static > electricity can do wonders. The bull naturally looks for romance even when a > storm is coming. Saint Elmo's fire can take all the romance outa the fun.. > or visa-verse. > Visible static electrical charge playing across cattle horns don't make a > lick of science sense... or does it ? Hmmm. the horns are an ideal opposite > of an ion exchange resin. That should get a charge outa Jones <grin> > > Richard > >
