Line formation of high-intensity Heβ-Rydberg dielectronic satellites 1s3lnl′ in dense laser-produced plasmas

On the basis of experimental and theoretical investigations it is demonstrated for the first time that in cold dense optically thick laser-produced plasmas, created near the target surface, the capture into the He-like ground state 1s 2 + e - → 1s3lnl′ is negligible for line formation and that observed high-intensity He β-Rydberg satellite intensities are correlated with highly populated He-like excited states 1s2l. X-ray emission spectra with simultaneous high spectral (λ/δλ ≈ 10.000) and spatial resolution (δx ≈10 μm) provide a direct verification of the proposed excitation mechanism. Atomic data calculations for all configurations with n = 3-6 have been carried out and were employed in spectral modelling. Taking into account the proposed excitation channels, excellent overall agreement is found. Successful cross-checks with the spectral interval near the He α-line are demonstrated. The spectral modelling is proposed for sensitive density (electron density, excited state population) and temperature diagnostics near the target surface.