$\require{mhchem}$I made a fusor once, like the easy science project: deuterium-deuterium ones, but they're really inefficient. I was wondering if it would be possible to make a small tokamak; not one that will make a ton of power, but I just want to make one for the sake of making one, like a tokamak the size of a pizza box. What materials would I need and how would I go about assembling it? Assume it is deuterium-deuterium or $\ce{p-^11B}$ fusion, maybe $\ce{^3He-^3He}$.
[Physics] How to make a small tokamak
electromagnetismhome-experimentmagnetic fields
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The magnetic haematite beads commonly sold as being good for you in some ill defined way are actually a mixture of haematite and magnetite. The magnetic field is generated by the magnetite.
At room temperature haematite is weakly ferromagnetic but not enough to be easily noticeable. It is only paramagnetic above 948K.
A "static" magnetic field, like you get from a bar magnet, is unchanging. Earnshaw's theorem says that there is no configuration of these stationary magnets alone which can keep another magnet in one place.
If you have magnets which are rings, for example, you may notice that if you put them both on a pencil sticking through the middle, pointing up from a desk, in one of the ways you orient them, they stick together; in another way you orient them, one of them floats above the other one. But you may also notice that you cannot keep the one on top floating without the pencil in the middle to hold it in place. It will always find some way to twist around so that it can stick to the other magnet.
Earnshaw's theorem says that actually, no set of magnets will do this. If you use a stronger magnet to try to discourage twisting, then the stronger magnet will now induce some other direction which the object wants to twist around in order to attract to the new bigger magnets. You cannot win.
It also says the same thing even if you add electric charges to all of your magnets, too. There is always a direction that the object can move which will reduce its electrostatic potential energy, and when it does so, it will gain some kinetic energy moving in that direction, twisting it out of its normal configuration.
With that said, we can break the assumptions of the theorem by using things like superconductors or computers that dynamically change the fields. We just can't do it "passively."
Best Answer
High Magnetic Fields. Not the answer you were looking for, but probably the true answer to the question "How dio you make a small(er) (working) tokamak?" It might even be the right approach in the long run. Google "ignitor fusion reactor" or "Bruno Coppi" for more information. The MIT Alcator is an example. Of course high field magnets have their own costs, problems and dangers, as do high magnetic field tokamaks. You should probably not try this on your kitchen table at home and expect a good result unless your resources are roughly equivalent to MIT, ITER or maybe even Florida State.
For a fusion related experiment (even vaguely tokamak related) that might be doable at home, look up "induction plasma technology" in Wikipedia. You might even find references under "Q-tube plasma" if you search hard enough. (Q-tubes were used in very early fusion research.) For more excitement and more danger, but a less tokamak like approach, look up "theta pinch"