ABSTRACT
A possibility to generate subfemtosecond X-ray pulses on relativistic ions and coherent X-ray spectroscopy on this basis is considered. The coherent and noncoherent amplification of short X-ray pulses is analyzed. The possibility of generation of ultrashort attosecond (10‒18 sec) X-ray pulses with intensities up to 1021 W/cm2 is considered.
