Dynamics of an intense laser-driven multiwell system: A model of ionized clusters

We have presented a two-dimensional multiwell model to simulate the inertially confined ionized clusters of which unscreened ions contribute attractive potential wells to other nearby atoms. Dynamics of the intense laser-driven multiwell system has been explored. When the multiwell system is irradiated by an intense laser pulse, it will emit enhanced high-order harmonic radiation in the process of avalanche multiphoton ionization. Three facts, namely, the combined potential configuration lowering potential barrier, intermediate states resonance, and collision heating of electron with ions, are responsible for the avalanche ionization of clusters. And the enhanced high-order harmonic generation is attributed to a higher ionization potential and greater polarizability of the active electron in the clustering multiwell system. We can conclude that the cluster is a highly efficient nonlinear medium for coherent short-wavelength radiation, especially when an ultrashort $(<\mathrm{}100\mathrm{}\mathrm{fs}),$ medium intensity laser pulse is used.