Re: Ionisation Q.

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

Original poster: "Antonio Carlos M. de Queiroz by way of Terry Fritz <twftesla-at-uswest-dot-net>" <acmq-at-compuland-dot-com.br>

Tesla list wrote:
> 
> Original poster: Jason Petrou <jasonp-at-btinternet-dot-com>
> 
> You would need a hugely powerful laser to ionise 5 miles of air between you
> and the cloud! also how would you store the energy from a cloud, seeing as a
> single discharge contains many billions of coulombs of electrons, and there
> are several discarges from a cloud every second - we are talking more power
> than runs through NYC's electricity grid! you would need to build a
> *massive* cap bank to store the charge, and then to use it in a TC you would
> have to drain it slowl like a battery.... it would never work!!!

A typical single lightning stroke transfers no more than 5 Coulombs of 
charge. Considering a voltage of 100 MV between cloud and ground, a
lightning stroke then dissipates 500 MJ.
(Source: Martin A. Uman, "Lightning" ISBN 0-486-64575-4)

If all this energy could be recovered, it could light 1389 100 W
lamps for one hour. This is not so much energy.

The inverted Tesla coil for efficient conversion of high-voltages to low
voltages is not an absurd idea, but for this application the terminal
that receives the stroke, and keeps it's full charge stored would have
to be huge:
Consider a sphere terminal, that is to receive the lightning stroke and
keep it's full charge at 50 MV, making available for transfer to lower
voltage one half of the energy of the stroke. The capacitance of this
terminal would have to be C = 5/50e6 = 100 nF.
Considering that the capacitance of a sphere is 111 pF per meter of
radius,
the terminal would have to be a sphere with 900 meters of radius.
(An association of smaller spheres is another possibility, each with
the surface electric field limited to 30 kV/cm. I leave the calculation
as exercise).

Antonio Carlos M. de Queiroz