TSSP: List Archives

From: "Malcolm Watts"
Date: Fri, 6 Aug 2004 17:59:54 +1200
Subject: RE: [TSSP] Secondary dynamic Efield

Hi Terry, Marco, all,

On 5 Aug 2004, at 18:10, Terrell W. Fritz wrote:

> Hi Marco,
> 
> See the animations at:
> 
> http://www.abelian.demon.co.uk/tssp/pn040502/
> 
> I am not sure the waveforms would have very good uniformity along the
> length of the coil as it was being fired.  The harmonics and
> non-linear effects can be pretty large.
> 
> The only way I know of doing it would be with a capacitive voltage
> divider through the secondary that also has an electrostatic shield. 
> That is how the Jennings and  Tektronix style probes work at high
> voltages and high frequencies without nearby fields messing the
> reading up.
> 
> Here is a diagram of the Jennings 60kV vacuum probe:
> 
> http://hot-streamer.com/temp/Jennings-JP-325/Diagram.jpg
> 
> A bunch of pictures are at:
> 
> http://hot-streamer.com/temp/Jennings-JP-325/
> 
> Of course, the shield is grounded and needs some pretty remarkable
> insulation....  But it could give the true high frequency top voltage
> of a coil.
> 
> Cheers,
> 
>          Terry

There might be fishooks in using a shielded probe through the centre. 
If the shield is continuous, it will form a shorted turn which will 
be coupled to some degree to the resonator and if the shield is an 
insulated overlap type, it will form its own resonant circuit, albeit 
with some very high Fr. Would an unshielded divider not be the way to 
go? Field strengths between the probe and various sections of the 
resonator would then be minimized and we can gauge the loading by 
remote monitoring of a shift in the resonator's Fr and electric field 
strength (non-sparking). Could a probe be graded to match the voltage 
profile? Alternatively, the profile could be linearized through the 
use of a very large topload which would then minimize the probe's 
influence.  To my mind, we have got to attain this goal somehow. 

Malcolm




Maintainer Paul Nicholson, paul@abelian.demon.co.uk.