Magnetic 'Coulomb' barrier

Abstract

The Coulomb barrier is a classic introductory physics concept and one that is key to understanding nuclear fusion. Yet the idea that fusing nuclei within a single system 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 behaviour and no commercially available demonstration kits. The magnetic 'Coulomb' barrier allows a visual and tactile demonstration of the central challenge of nuclear fusion: overcoming the electrostatic forces inherent in the Coulomb barrier. Students directly determine the kinetic energy required to overcome the magnetic potential energy barrier. The Magnetic 'Coulomb' Barrier won first place at the 2023 American Academy of Physics Teacher Apparatus Competition in Sacramento, California, USA.