Nanofoam in action: a versatile tool for laser-plasma interaction experiments

Low-density near-critical materials in laser-plasma interaction (LPI) stand out for their capability in enhancing the coupling between the laser radiation and the target. Indeed, they can be exploited for fundamental physics studies, optimised particle acceleration for practical applications, and inertial confinement fusion. However, the modelling of complex non-linear phenomena occurring during the interaction of these materials and high-intensity lasers, together with the accurate control and characterisation of their physical properties, are still object of intense research. In this context, near-critical nanofoams produced via pulsed laser deposition represent a promising option owing to the versatility and controllability of their deposition technique. In this paper, we report on our modelling and experimental activities related to laser-nanofoam interaction. In particular, we first present the deposition methodology, focusing on the production of nanofoams with controlled composition and morphology. Then, we show our numerical strategy to model the foam aggregation. We also discuss how the nanofoam morphology affects the LPI by integrating the realistic nanostructure in particle-in-cell simulations, focusing on various regimes of interaction. Lastly, we present examples of applications of nanofoam-based targets via numerical simulations and experiments, focusing also on the open issues for reaching the requirements for full-fledged applications. Our work demonstrates nanofoam-based targets as a versatile tool to effectively optimise and advance LPI physics.