Magnetic “Coulomb” Barrier

24 January 2023, Version 1
This content is a preprint and has not undergone peer review at the time of posting.


The Coulomb barrier is a classic introductory physics concept and one that is key to understanding nuclear fusion. Yet the idea that fusing atoms could exhibit both far-range repulsion and short-range attraction can result in significant cognitive dissonance in students. There are no classical examples of this behavior and no commercially available demonstration kits. The magnetic potential energy barrier apparatus allows a visual and tactile demonstration of repulsion at a distance and strong short-range attraction. Students directly experience the role of kinetic energy in overcoming a potential energy barrier.


Coulomb barrier
Magnetic potential
educational aids
potential energy barrier
nuclear fusion
newtonian mechanics
chaos theory
plasma confinement

Supplementary materials

Magnetic "Coulomb" barrier video abstract
A pair of magnet arrays each containing a series of alternating/unequal magnets demonstrates repulsion at a distance and attraction at close range. This models the behavior of the Coulomb barrier.
Materials list and force/distance data between a pair of magnetic "Coulomb" barrier arrays
This spreadsheet contains raw data and materials list.

Supplementary weblinks


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