Re: Streamer modeling

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Antonio Carlos M. de Queiroz" <acmdq@xxxxxxxxxx>

Tesla list wrote:
> Original poster: Terry Fritz <teslalist@xxxxxxxxxxxxxxxxxxxxxxx>
> Hi All,
> I had a chance to look through the book "Spark Discharge" and it appears 
> they have things pretty much figured out!!  They come up with most of the 
> same numbers we do and add some wonderful things like "optimal rise time" 
> :-))))   111uS for a 2 meter streamer ;-))
> They get about 1.9pF/foot for streamer capacitance which is pretty close 
> to our "average" number taking various factors (slow resonant rise) into 
> account.  It is pretty straight forward adding a dynamic model to ScanTesla...
> They have some pretty good math behind their numbers but they obviously 
> really "checked it" too ;-))
> The book is actually worth $130!  It is from CRC Press too (which 
> apparently has presses made of gold, diamond, and platinum....) so it is 
> cheap for their books!
> I will do some test (or maybe E-Tesla can do it) to better lock down the 
> numbers for our case and see if I can get it into ScanTesla...

It's simple to change the code to allow time-varying elements. I am testing
now a version of the calculation engine where the capacitances and resistances
can change. The present model for the streamer load, C2 (part), R3, and C3,
can then be made to change to simulate breakout and streamer growth.
The problem is how they change. In a first approximation I am trying to
leave R3 constant and increasing C2 and C3 when the terminal voltage
exceeds a certain breakout voltage, by equal amounts that return the terminal
voltage to about the breakout voltage. The result is that the load capacitance
increases at the voltage peaks, and more power is dissipated in the fixed
streamer resistance R3. Detuning limits the increase at some point.
If this makes sense, streamer length can be estimated by the increase in
the streamer capacitance.

Antonio Carlos M. de Queiroz