X-RAY-SPECTRA OF MULTIPLY-CHARGED HOLLOW IONS IN THE EMISSION FROM A FEMTOSECOND LASER-PLASMA

A new type of quasicontinuous emission spectrum from a femtosecond las er plasma near the Ly alpha line of H-like ions is obtained and interp reted. It is shown that these spectra are emitted by multiply charged hollow ions, which are present in the plasma on account of its ultrahi gh density, which, in turn, is due to the use of high-contrast laser p ulses for producing the plasma. A new spectroscopic approach based on analysis of the composition of spectral complexes of hollow ions is di scussed. (C) 1998 American Institute of Physics.