A tokamak is a device designed to confine and control hot plasma using magnetic fields, primarily for the purpose of achieving nuclear fusion. It features a doughnut-shaped chamber where plasma is heated to extremely high temperatures, allowing atomic nuclei to collide and fuse, releasing energy. The magnetic fields are generated by coils surrounding the chamber, which help maintain the stability of the plasma. The concept of the tokamak was developed in the 1950s in the former Soviet Union and has since become a leading approach in fusion research. Successful tokamak experiments, such as those conducted at facilities like ITER and JET, aim to demonstrate the feasibility of fusion as a clean and virtually limitless energy source.