Superradiance and related phenomena
National Research Centre ‘Kurchatov Institute’, pl. akad. Kurchatova 1, Moscow, 123182, Russian Federation
The current theory of superradiance is described. The effect is due to interatomic correlations (phase-locking) which arise under the action of a general electromagnetic field and are determined by the competition between the electron motion anharmonicity and the interatomic dipole-dipole interaction. The latter affects significantly the nature of the superradiance effect. A common nature for the radiations from a Dicke atomic ensemble and from collective waves in a substance (for example, cyclotron waves in a magnetized plasma) is established. Superradiance manifests itself in hot magnetically confined plasmas and accounts, among other things, for anomalous heat conductivity in tokamaks.