Coherent X-ray radiation by ensemble of different charge particles in matter

The kind of X-ray bremsstrahlung radiation – coherent polarization bremsstrahlung radiation (PB) by ensembles of the fast charged particles (multi-charge cluster) at their interaction with the structured matter is considered. Physical bases and conditions of PB observation are discussed. Some new coherent PB effects connected with the mutual screening in ensembles containing positive and negative charged particles and transformations of PB spectra in crystal target are indicated.