A question from a complete novice:

Perfectly aware that tokamaks confine plasma in a toroid, could they potentially generate an axial vertical electro-magnetic field as a side-effect, or is it completely out of the question (of course, assuming that no external magnetism is generated, apart from the toroid confining plasma). Assuming that an ITER Experimental Tokamak will generate around 500MW of power could we possibly reconvert it into nT (nanoTeslas) that plasma would generate in such a case? A more Sci-Fi scenarion: Would it have any influence at all on the Earthly geomagnetism (as in - local), if in fact such an axial horizontal field would develop, having in mind the current WMM Model 2020 (https://www.ngdc.noaa.gov/geomag/WMM/)?

I've encountered an excerpt from a book that touches this subject:

TY - BOOK AU - Garza-Ulloa, Jorge PY - 2019/04/03 SP - T1 - Electromagnetic Field Toroidal And Magnetic Confinement Fusion Tokamak DO - 10.13140/RG.2.2.17211.67362 ER -


could they potentially generate an axial vertical electro-magnetic field as a side-effect

They do, it's an important part of the stability when the reactors get over a certain size. That's because due to gravity and the natural tendencies of fluids in a gravitational field, the density changes vertically. That's bad when you start inducing megamamps into it.

So they add a second field that mixes with the main magnets to counteract this. They're called the poloidal magnets, although in modern machines they have many purposes, not just this one.

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  • $\begingroup$ Thank you very much for your most knowledgeable answer. I am perfectly content with it and satisfied that it wasn't a foolish question. Kind Regards Maury. $\endgroup$ – Wolves' Shepherd. Feb 8 at 14:16

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