Subject:  Re Dry lightning (Lilja) (Philips)....  (fwd)
Date:     Tue, 28 Sep 1999 042745 -0500 (CDT)
From:     "Roy L. Beavers" 
To:       emfguru 
--------------------------------------------------



---------- Forwarded message ----------
Date: Mon, 27 Sep 1999 18:10:14
From: Alasdair Philips 
To: "Roy L. Beavers" , emfguru 
Cc: "Wolfgang W.Scherer" , ilkka A Lilja 
Subject: Re: Dry lightning (Lilja).... 

Er, um, ??
Earth Ionosphere voltage is typically 300,000 Volts DC.  Agreed.
+ve at the Ionosphere with respect to -ve at the Earth.

Earth Ionosphere distance is between 50 and 400 kilometres.
Assuming most cgarge to be effecitively in the middle of the
Ionosphere (E/F layers) at say 150 to 200 km above the Earth.
This gives us a voltage gradient of 300,000/150,000 = 2 volts/metre

In fact, due to different ionic conductivities the actual gradients
in fair weather are 10 V/m at 10 km up, 30 V/m at 1 km up,
and 100 V/m DC at ground level.

Clouds are typically between 1 km and 10 km above the Earth.
Within upper and lower layers of storm clouds fields of up to
at least 500,000 volts/metre exist.

Fields between thunder clouds and the Earth are often negative
(i.e. reverse from normal) and between 1000 and 50,000 V/m.

High and pointed structures such as towers cause the air near them 
to be more ionised than surrounding air and this leaks upwards 
meeting other charged streams coming downwards from the clouds 
typically 1 to 5 km high. When the air under the clouds becomes 
sufficiently ionised the tracer starts out towards the earth. 

Once the conductive path has been established lightning proper 
occurs, stepping downwards in steps of 50 to 100 metres at a time 
with short (50 microseconds) pauses. The current to the Earth can 
be in the order of 10,000 Amps. This is followed by a return 
current surge which can be up to double that.

I can't see how a small tower of 15 to 75 metres high can 
significantly influence things without storm clouds when we
are looking at many 1000s of metres to get a high potential.
You need some tens of thousands of volts/metre to trigger
lightning.
I am open to persuasion, but on my understanding of the science
I can't see how 'no clouds lightning' can occur.

Good wishes
Alasdair
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Alasdair Philips,   BSc(Eng), DAgE, MIAgE
Director, UK Powerwatch, (aphilips@gn.apc.org)
EMC Engineer and EMF-bioeffects researcher
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

At 08:55 27/09/99 -0500, Roy L. Beavers wrote:
>......This is very interesting....  I hope someone can confirm this
>phenomenon....  Thanks, Ilkka.....
>
>Roy Beavers (EMFguru)......
>---------- Forwarded message ----------
>Date: Mon, 27 Sep 1999 12:10:55 +0300
>From: ilkka A Lilja 
>To: WWS 
>Subject: towers
>Resent-Date: Mon, 27 Sep 1999 09:52:34 +0000
>Resent-From: "Wolfgang W.Scherer" 
>Resent-To: rbeavers@llion.org
>
>There may cases where the earth -ionospheric EMF of 300 000 Volts (300
>V/m
>on aerage at the 2 m height on fair weather, and in the vicinity of
>thunderstorm/ cumulonimbusclouds  5000 V/m) and a certain geometrical
>siting
>(or topology)  of metal radio towers can result electrical fields that
>even makes
>a dry lightning (no clouds lightning) resulting problems at farms and
>homes
>
>Also ICAE99 had papers related to towers and lightning
>
>regards  ILkka A Lilja
>                weather physicist
>                Jyvaskyla
>                 Finland
>
>
>
>
>
 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Alasdair Philips,   BSc(Eng), DAgE, MIAgE
Director, UK Powerwatch, (aphilips@gn.apc.org)
EMC Engineer and EMF-bioeffects researcher
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~




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Reprinted with permission of Roy Beavers, http://www.emfguru.com