RE: Terry's New Plane Wave Antenna

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Marco Denicolai" <marco.denicolai@xxxxxxxxxx>

Hello all,

> -----Original Message-----
> From: Tesla list [mailto:tesla@xxxxxxxxxx]
> Sent: Monday, December 26, 2005 18:00
> To: tesla@xxxxxxxxxx
> Subject: Re: Terry's New Plane Wave Antenna
>
> Original poster: "Gerry  Reynolds" <gerryreynolds@xxxxxxxxxxxxx>
> <SNIP>Seems
> like calibrating at NST voltages with 60 Hz would work just fine if
> streamers and corona did not happen to distort the e-field from what
> exist at 60 Hz. Not sure about this so please comment.

The major sources of field distortion are, IMHO, three:
- space charge left by previous discharges. It takes several tenths of
milliseconds to get to low values. Practical breakdown experiments usually
wait for 30s-60s between shots.
- elongation of the discharge. The Efield along the discharge has got a peak
on the leader head and a second 4-5 Kv/cm peak on the streamer umbrella
extremity. As these travel along the gap, the peaks travel as well.
- as a consequence of the above, direction of the discharge i.e. relative
position of the antenna.

The grounded antenna "backplane" distorts the Efield too, but that is the
same for 60 Hz or a real streamer.

All in all, I suppose the antenna AC calibration is at its best (validity)
when measuring single bangs, far apart from each other, that don't produce
corona or streamers.

Regards