stray DC on Tesla Coil

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "davep by way of Terry Fritz <twftesla-at-qwest-dot-net>" <davep-at-quik-dot-com>


> Personally, I've tried all the inductance formulas and none of them match
> the measured inductances of the coil.  I have gotten extremely high
> electrostatic voltages from these wye coils by putting a strong
> electrostatic capacitance on the terminal.  I have identified a clear
> electrostatic potential between the space below and the space above the flat
> spiral coil.  How many of you have a solenoid that shows a coil with one end
> continuously at a negative potential and the other end continuously at a
> positive potential (actually it might exist between the center of the
> solenoid and the space around the outside of the solenoid?  Maybe somebody
> could check this.)

	Several have reported this with classic 'solenoid' coils.
	One might check the list archives.  Last time is was
	something like 'strange sparks' or 'strange charges'.

> The vector of energy in a flat spiral is clearly in one direction, from the
> outside toward the center.  As far as I know, solenoids are RF all the way
> through.

	Common assumption.  It having been reported, repeatedly, that
	a DC component is present, various explanations have been
	proposed.  For persistence of charge, look up an electret
	or electrophorus.  (A thing which stores electric charge, more
	or less as a magnet stores magnetic 'charge'.)

	For the presence of DC field, while in operation (and for the
	source of the DC field to charge the 'electret', look for
	something called an 'ionic rectifier' (or close to that, the
	proper name is in the list archives.)

	Roughly, what happens is that the leakage current from a quasi
	pointed electrode at high AC potential is asymmetrical, leading
	to (inefficient) rectification.  This was used in HV rectifiers,
	for some purposes, in decades past.  Roughly, one might say that
	since the positive ions are atoms (large), and the negative largely
	electrons (light) there is a different mobility for each, leading
	to the asymmetry, hence, the rectification...

	This can be found in the usual texts, eg 'Gaseous Conductors',
	Cobine
	best
	dwp