The Density Distribution of Electrons Induced by Multi-petawatt Laser Coupling with Gas Jets

The laser pulse was simulated as being incident directly onto a 1 mm nitrogen gas jet. A linearly polarized laser beam with a wavelength of 800 nm, a duration of 30 fs, a diameter of 5 μm, and an intensity of 5 × 1020 W/cm2 was employed.

The electron densities of the nitrogen gas jets were set at 0.023 nc, 0.033 nc, 0.05 nc, and 0.0706 nc, where nc=1.7 × 1021 cm-3 denotes the critical plasma density for an 800 nm laser. Figures (a) to (d) depict the density distribution of hot electrons generated by the interaction between the multi-petawatt laser and the nitrogen gas jets at the aforementioned pressures.