Electrical fields

Hi,

Thats an interesting picture. The explanation that goes with it doesn't tell you much about what phenomenia is being pictured - but if you follow the links to 'Sandi Lab' then 'pulsed power' you will arrive at link where it says "Time-exposure photograph of electrical flashover arcs produced over the surface of the water in the accelerator tank as a byproduct of Z operation. These flashovers are much like strokes of lightning"

So what is being recorded is not the electromagnetic field but rather the sparks (small lightning) produced by arcing between different parts of the machinery. If this happened in a powerstation then I think there would be a serious malfunction in progress...

The picture appears to be an 'ordinary' long exposure just with a lot of sparks going on.

The only way of taking a photograph of a magnetic field would be by recording its action on something else (eg the iron fillings mentioned previously).
Several years back there was an 'Art Installation" near Bristol where flourescent light tubes were partly buried in the ground so that about 3/4 of their length was pointing up to overhead high voltage power lines. At night the electro magnetic field made the florescent tubes glow and by touching them it was possible to change what parts of the tube glowed and even the colour.

That's the closest I've come to taking a picture of an electromagnetic field. I'll try and find a picture and add this tonight...

Good luck
Bob

The shot is of the z machine producing a massive electrical discharge. The z Machine is one of the routes the search for viable nuclear fusion has so far culminated in, and is basically recreating what happens in the heart of a star. There was an excellent Horizon programme on BBC about the fusion race. The machine released about 80 times the world's entire electrical power usage (half a trillion watts) for a brief fraction of a second. As far as I understand it the visable light is plasma - a partially ionized gas, in which a certain proportion of electrons are free rather than being bound to an atom or molecule. The ability of the positive and negative charges to move somewhat independently makes the plasma electrically conductive so that it responds strongly to electromagnetic fields. The colours are a result of relaxation of electrons in excited states to lower energy states after they have recombined with ions. These processes emit light in a spectrum characteristic of the gas being excited and is known as filamentation.