Re: Impedance of Corona or Arcs vs Voltage (fwd)

---------- Forwarded message ----------
Date: Sun, 12 Jul 1998 23:35:56 -0500
From: Bert Hickman <bert.hickman-at-aquila-dot-com>
To: Tesla List <tesla-at-pupman-dot-com>
Subject: Re: Impedance of Corona or Arcs vs Voltage (fwd)

Tesla List wrote:
> ---------- Forwarded message ----------
> Date: Sat, 11 Jul 1998 06:29:06 -0600
> From: terryf-at-verinet-dot-com
> To: tesla-at-pupman-dot-com
> Subject: Impedance of Corona or Arcs vs Voltage
> Hi All,
>         Does anybody know how the resistance (impedance) of either corona or
> TC arcs to space increase with voltage?  Ie what function defines the drop
> in impedance as voltage increases?
>         Also, does anybody care to guess what those impdeance might be?  I
> get from the low hundreds of Kohms out to the low mega ohm region.
>         I just thought I would ask.  There should be some information on
> corona loss at least.
>         Terry Fritz


Some further information/confirmation. I made some "single shot"
measurements on my 10" coil, and back-figured the effective Q of the
secondary for "no breakout" and "breakout" cases (air streamers, not
ground arcs). 

Based upon ringdown measurements, the estimated no-breakout Q of the
secondary:toroid was around 190. This implies that corona losses (at
least for this particular system) are relatively low when the top of the
secondary is "shaded" by the non-breaking toroid.

With breakout, the secondary Q dropped to about 29, which, based upon my
coil's parameters, implies a single-shot Rarc of about 1.2 Megohms.
Under full power heavy streamer loading, this would undoubtedly drop to
a significantly lower value. Previous measurement estimates for power
arcs to ground implied an Rarc of about 7000 Ohms.

-- Bert --