Cyclic particle accelerator in which the particle is confined to its orbit by a magnetic field .
The strength of the magnetic field increases as the particle's momentum increases. An alternating electric field in synchrony with the orbital frequency of the particle produces acceleration. Synchrotrons are named according to the particles they accelerate. The Tevatron, a proton synchrotron at the Fermi National Accelerator Laboratory in Illinois, U.S., produces the highest particle energies achieved so far.