The electromagnetic radiation emitted when charged particles are accelerated radially () is called synchrotron radiation. It is produced, for example, in synchrotrons using bending magnets, undulators and/or wigglers. It is similar to cyclotron radiation except that synchrotron radiation is generated by the acceleration of ultrarelativistic charged particles through magnetic fields. Synchrotron radiation may be achieved artificially in synchrotrons or storage rings, or naturally by fast electrons moving through magnetic fields. The radiation produced in this way has a characteristic polarization and the frequencies generated can range over the entire electromagnetic spectrum.