Numerical study on prolonging lifetime of plasma channels generated by ultra-short laser pulses

The density and decay kinetics of a plasma channel produced in air by a self-guided intense femtosecond laser pulse is investigated by numerical simulation method. The two-body, three-body dissociation attachment and the recombination of the free electrons, positive and negative ions are considered in the theoretical model. The influence of dissociation attachment caused by the subsequently incident laser on the generated plasma channel has been studied and the effective control parameters of the subsequent laser can be obtained. The calculation shows that the lifetime of the channel is sensitive to the initial conditions of the subsequent laser and the relative delay between the subsequent laser and the maximum plasma density. The corresponding lifetime of the revived plasma channel can be efficiently extended to more than 25 s, in the case that the subsequent laser is sufficiently controlled under optimum parameters.