An Abundance of Extremely Large Clusters As a Target for Intense Laser-Matter Interaction

The advent of very intense, short-pulse lasers changed dramatically the field of laser-matter interaction. The interest in new forms of target brought clusters to the forefront as a very promising and unique medium. Here, extremely large Xe or CO_2 clusters embedded in an abundance of smaller ones were formed and subsequently irradiated by intense laser pulses ( ≲ 10^19 W/cm^2 ) to demonstrate the specific character of such a medium and its suitability for intense laser-matter interaction. Emission of short-wavelength radiation quantified in the spectral range known as the “water window” constituted the reference for the target performance. The clusters were formed in a double-stream gas-puff equipped with a gas reservoir cooled down to 245 K and backed by a low-to-moderate pressure of ≤ 12 bar . The obtained atomic/molecular compounds, mostly of an irregular shape and of an average diameter ≃ 2.4 ± 0.5 m in the case of Xe and ≃ 2.0± 0.4 m for CO_2 , have been imaged by optical microscopy while the size was determined by the standard scattering method. A scenario explaining the formation of such clusters has been proposed. The interaction results show that a photon/particle source can be copious when based on the developed target technology with an abundance of the extremely large clusters. These clusters enable also the experiments with a single-cluster target.