Re: Measuring Streamer characteristics

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

Original poster: "Bob (R.A.) Jones" <a1accounting-at-bellsouth-dot-net> 


  Hi all,

Some additional observations and some brain storming.

 > oscillation idea when the streamer connects to ground.
 >
 > Assuming the first paper is a streamer to air, in one cycle the streamer
 > current develops in to an in phase (aprox) current with top load voltage.
 > A visual estimate of the predominantly resistive impedance is 240kV/0.8A =
 > 300k . The streamers were believed to be between 12 and 24 inches long.
 > Of cause  a better value could be obtained from processing the data
points.


That's about 192kW peak required to grow a 12 to 24in streamer!!!!

Lets assume the duration was 25us the energy was 192,000 * .707*.000025 =
3.3J.

As cross check I checked what the primary bang J was.

0.5*16700*16700*2.7*10**-9= 0.377J !!!!

Obviously a problem some where. perhaps my calcs or interpretation.

I tried the Frau formula on 0.3777J * 120 and got 11.4in

What I was trying to get a feel for was what the input power had to be to
grow the spark
In my proposed SSTC the power is going to be more like 7kW or less (during
the burst)
This is much less than the above.  So I assume after break out and initial
stream growth from the energy stored in the top load there would be very
little additional streamer growth from the  power input.
If that level of power is required to grow a 12/24in streamer then a low
peak power (300V, 100A) SSTC must rely on getting the power relatively
slowly in to the top load and letting the stored energy do the rest after
break out. It may also mean that a low frequency(50kHz) system has an
inherent disadvantage because it is supplying the power over a longer period
and hence the total energy will be higher.
i.e. if the streamer is growing from cycle to cycle the longer the period
the greater the energy required to maintain the streamer.

Does any one know if you can form a long streamer on the first peak or does
it always require several cycles?

  Bob