Light produced by charged particles when they pass through an optically transparent medium at speeds greater than the speed of light in that medium.
For example, when electromagnetic radiation that appears as a weak bluish-white glow. The phenomenon is named for Pavel A. Cherenkov (1904–1990), who discovered it; he shared a 1958 Nobel Prize with Igor Y. Tamm (1895–1971) and Ilya M. Frank (1908–1990), who interpreted the effect.