Physics, Mathematics, Fusion Energy, Engineering, Plasma Physics.
https://commons.wikimedia.org/wiki/File:Hairy_doughnut.png Plasma inside the TCV tokamak. Source: https://actu.epfl.ch/news/epfl-and-deepmind-use-ai-to-control-plasmas-for-nu/ This is precisely why the majority of current fusion reactor designs opt for a toroidal shape. Fusion plasma confinement