ABSTRACT

We investigate the effects of electron density on the intense femtosecond laser filamentation in air and argon. We consider the avalanche ionization, attachment and recombination process which could influence electron density. Simulation results show that these effects on the on-axis intensity can be neglected when the pressure is low, and then increase to be almost constant with the increasing pressure. These effects in argon are more obvious than those in air. They should be taken into account in the simulations of the femtosecond filamentation in the high pressure environment larger than 10 atm and 20 atm for argon and air, respectively.