Re: Surface Arcing Photo

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

Original poster: "Greg Leyh by way of Terry Fritz <teslalist-at-qwest-dot-net>" <lod-at-pacbell-dot-net>


>Hi all,
>web surfing i came across this
>http://www.lod-dot-org/teslacoils.html
>man sitting in a cage electrode on top of his large coil.
>He is safe from electric fields there (well known Faradey cage effect),but 
>i was wondering what about magnetic fields.?
>I suspect part of magnetic field could enter hollow sphere and induce 
>currents in man's body.
>How real is danger of that possibility?
>Rik


I'm sure he's ok... although the ozone may have affected his sanity.

Regarding the magnetic field component, the website mentions:
The currents in the top winding are about 50A peak
The # of turns per meter in the secondary is about 200.

The basic equation for a solenoidal field is:
B = 4pi*10^-7 * N/m * I

which yields:

B = 4pi*10^-7 * 200 * 50
B = 0.01256(tesla) = 126(gauss)

126G is not much of a field to start with, and the conductive cage
of the sphere attenuates it considerably further from there, given
the high frequency of the magnetic field.  An attenuation of as little
as 44dB would bring it down to the Earth's field level.