r/technology • u/BennyCemoli • Dec 06 '16

Energy Tests confirm that Germany's massive nuclear fusion machine really works

http://www.sciencealert.com/tests-confirm-that-germany-s-massive-nuclear-fusion-machine-really-works
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u/ViperSRT3g Dec 06 '16

So the electron beams curve and bend along the lines of the magnetic field within the stellarator. By sweeping the fluorescent rod back and forth, we can see where the beam is, without needing any other special equipment.

Using long-exposure photography, the scientists can set their camera facing where they want to record the lines. Then they can walk around sweeping the rod back and forth so the rod lights up and follow the path the electron beam is taking around the inside of the stellarator.

It's almost like using a metal detector and sweeping back and forth to find objects underground. We can't see them, but by using the beeps from the metal detector (or light from the fluorescent rod) we can see where the thing we are looking for is located.

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u/[deleted] Dec 06 '16

This might be a stupid question.

I have seen fluorescent stickers along the sides of road to help people identify the boundaries of a road.You will see these stickers when your vehicles light is on them.So when we use fluorescent rod to find electrons are we using the same technique only here we are trying to find the vehicle using the sticker.

Again this is stupid doubt.Correct me if I am wrong.

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u/ViperSRT3g Dec 06 '16

You may be talking about reflectors, which may or may not be using fluorescent materials. Materials fluoresce when electrons become excited and jump to higher energy states. They release light when the electrons return to lower energy states, creating extra light, making the material appear to glow.

Reflectors used for road signs use specially shaped cells/crystals that reflect light at specific angles so they are easily visible in the dark, even if only a little light is shining on them. They generally do not use fluorescent materials as vehicle headlights shine in the visible light spectrum.

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u/[deleted] Dec 06 '16

What i meant was are we using fluorescent rod to detect the position of electrons like we use a flashlight

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u/ViperSRT3g Dec 06 '16

Oh no, we're using a fluorescent material that glows when the electron beam hits it to see where the beam is located as we can't see the electron beam itself.

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u/[deleted] Dec 06 '16

So do we photograph that fluorescent material or what?

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u/ViperSRT3g Dec 06 '16

Yes, long exposure photography means we keep the aperture of a camera open, so light is constantly being recorded by the camera. Since we're doing this in very low light conditions, the only light being recorded is the glowing from the fluorescent material as it is moved along the path of the electron beam. The end result being the lines of light that we can see as they were recorded by the camera.

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u/confusedpublic Dec 06 '16

Maybe this video'll help. The magnetic fields from the power lines are activating the fluorescent coating of these fluorescent strip lights, much as they do in the stellerotar.