Effect of ion motion on generation and lifetime of magnetic fields in a cluster plasma irradiated with intense circularly polarized laser pulses

We report a numerical and analytical investigation of the effect of ion motion on the temporal dynamics of a strong quasi-stationary magnetic field arising when submicron clusters are irradiated with circularly polarized radiation. A region of high-density magnetized ions is shown to appear in the central region of the cluster. This region has an increased lifetime compared to that of a cluster without a magnetic field. The presence of a magnetized region leads to a characteristic two-peak dependence of the magnetic field on time.