Fig. 1. Schematic of the simulation process

Fig. 2. Simulation results of two elliptical femtosecond laser beams propagating in air with a crossing angle 0.44°. Transverse pattern of laser beams intensity distribution at different distances

Fig. 3. Simulation results of two Gauss femtosecond laser beams propagating in air with a crossing angle 0.44°. Transverse pattern of laser beams intensity distribution at different distances

Fig. 4. Simulation results of two elliptical femtoseoncd laser beams propagating in air individually with a crossing angle 0.44° and without any interaction between two laser beams. Transverse pattern of laser beams intensity distribution at different distances

Fig. 5. Filament cluster number as a function of propagation distance

Fig. 6. Simulation results of two elliptical femtosecond laser beams propagating in air with a crossing angle 0.28°. Transverse pattern of laser beams intensity distribution at different distances

Fig. 7. Simulation results of two elliptical femtosecond laser beams propagating in air with a crossing angle 0.6°. Transverse pattern of laser beams intensity distribution at different distances

Fig. 8. Transmission of two crossing femtosecond laser beams in space with different angles

Fig. 9. Simulation results of two elliptical femtosecond laser beams propagating in air with identical frequencies and a crossing angle 0.44°. Transverse pattern of laser beams intensity distribution at different distances

Fig. 10. Transmission of two crossing femtosecond laser beams in space with identical frequencies and the corresponding filament cluster number as a function of propagation distance