On coherent radiative processes in crystallised ion beams

Periodic spatial structures formed by cooled beams of free ions of the same sign in traps of one or another type are considered. These structures can be treated as quasi-crystals. Coherent nuclear radiative processes proceeding in the beams depend on a regular arrangement of nuclei in the structure of such crystallised ion beams. These processes include the Dicke superradiance, directional emission of gamma quanta, the establishment of a distributed feedback, and the appearance of the hidden inversion of nuclear states. Conditions required for the emergence of these effects are quantitatively estimated.