X-ray radiation from ions with K-shell vacancies

New types of space resolved X-ray spectra produced in light matter experime nts with high intensity lasers have been investigated experimentally and th eoretically. This type of spectra is characterised by the disappearance of distinct resonance line emission and the appearance of very broad emission structures due to the dielectronic satellite transitions associated to the resonance lines. Atomic data calculations have shown, that rather exotic st ates with K-shell vacancies are involved. For quantitative spectra interpre tation we developed a model for dielectronic satellite accumulation (DSA-mo del) in cold dense optically thick plasmas which are tested by rigorous com parison with space resolved spectra from ns-lasers. In experiments with las er intensities up to 10(19) W/cm(2) focused into nitrogen gas targets, holl ow ion configurations are observed by means of soft X-ray spectroscopy. It is shown that transitions in hollow ions can be used for plasma diagnostic. The determination of the electron temperature in the long lasting recombin ing regime is demonstrated. In Light-matter interaction experiments with ex tremely high contrast (up to 10(10)) short pulse (400 fs) lasers electron d ensities of n(e) approximate to 3 x 10(23) cm(-3) at temperatures between k T(c) = 200-300 eV have been determined by means of spectral simulations dev eloped previously for ns-laser produced plasmas. Expansion velocities are d etermined analysing asymmetric optically thick line emission. Further, the results are checked by observing the spectral windows involving the region about the He-alpha-line and the region from the He-beta-line to the He-like continuum. Finally, plasmas of solid density are characteristic in experim ents with heavy ion beams heating massive targets. We report the first spec troscopic investigations in plasmas of this type with results on solid neon heated by Ar-ions. A spectroscopic method for the determination of the ele ctron temperature in extreme optically thick plasmas is developed. (C) 2000 Elsevier Science Ltd. All rights reserved.