Electromagnetic radiation emitted by relativistic charged particles following a curved path in magnetic or electric fields. Synchrotron radiation is generally produced in laboratories by a beam of relativistic (moving near the speed of light) electrons or positrons in a generally circular path in a specialized synchrotron called a storage ring. A storage ring produces electromagnetic radiation with high flux, brightness, and coherent power levels. Synchrotron radiation is used for a wide variety of basic and applied research in biology, chemistry, and physics, as well as for applications in medicine and technology.