A tokamak is a device used to create and contain a plasma, which is a state of matter that is similar to a gas but made up of ions and free electrons. It is often used in experiments related to nuclear fusion, in which two or more atomic nuclei combine to form a heavier nucleus, releasing large amounts of energy.
A tokamak is a donut-shaped device, while a spherical tokamak is a more compact version with a smaller hole in the middle. This difference in shape affects the way the plasma is confined and heated, as well as the stability of the device.
Both tokamaks and spherical tokamaks have been used in nuclear fusion experiments, and both have advantages and disadvantages. However, current research suggests that spherical tokamaks have the potential for higher efficiency due to their compact size and ability to produce a higher plasma pressure.
In both devices, a strong magnetic field is used to confine the plasma. This magnetic field is created by large superconducting coils surrounding the device. The plasma is heated using various methods, such as radio frequency or neutral beam injection, to temperatures of millions of degrees Celsius. This allows the particles to overcome their repulsive forces and fuse together, releasing energy.
Tokamaks and spherical tokamaks are primarily used in research and development for nuclear fusion energy, as they have the potential to provide a nearly limitless source of clean energy. They can also be used to study plasma physics, astrophysical phenomena, and materials science.