摘要
An investigation of the cluster size dependence of the maximum energy of protons ejected from explosion of methane clusters in an intense femtosecond laser field has been conducted on the basis of the cluster size estimation by Rayleigh scattering measurements. The interaction of a 2 × 10^16-W/cm^2 intense laser pulse （790 nm, 60 fs） with the methane clusters revealed that the clusters were Coulomb exploded and the maximum energy （Emax） of the protons produced was linearly proportional to the square of the cluster radius （rc^2）. In a cluster size range, with the methane cluster radii up to about 3 nm, the established relation of Emax and rc^2 was found to be Emax （keV） = 3.3 ＋ 0.75rc^2 （nm^2）, in good agreement with the simulation results. This demonstrated that Coulomb explosion of ionic clusters （C^＋4 H4^＋）n took place following the cluster vertical ionization in the laser-cluster interaction.
An investigation of the cluster size dependence of the maximum energy of protons ejected from explosion of methane clusters in an intense femtosecond laser field has been conducted on the basis of the cluster size estimation by Rayleigh scattering measurements. The interaction of a 2 × 10^16-W/cm^2 intense laser pulse （790 nm, 60 fs） with the methane clusters revealed that the clusters were Coulomb exploded and the maximum energy （Emax） of the protons produced was linearly proportional to the square of the cluster radius （rc^2）. In a cluster size range, with the methane cluster radii up to about 3 nm, the established relation of Emax and rc^2 was found to be Emax （keV） = 3.3 ＋ 0.75rc^2 （nm^2）, in good agreement with the simulation results. This demonstrated that Coulomb explosion of ionic clusters （C^＋4 H4^＋）n took place following the cluster vertical ionization in the laser-cluster interaction.
基金
This work was supported by the National Key Basic Research Special Foundation of China (No. G1999075200)the National Natural Science Foundation of China(No. 10535070).
