شبیه‌سازی ذره‌ای رشته‌ای شدن باریکه‌های لیزر در برهم‌کنش دو باریکه نسبیتی با پلاسمای کم چگال

By applying two relativistic high-intensity laser beams under different conditions to low-density plasma, the effects of the beams' corresponding distance and angle on their filamentation were investigated and studied. The results of the simulations using the particle in cell (SMILEI) two-dimensional code show that when the distance and the corresponding angle between the pulses are zero, the results are the same as a powerful pulse with intensity equals four times a single pulse. Meanwhile, it was clear that the impact of relative beam angles on pulse filamentation is more significant and sensible than the effect of distance variation. So, it is shown that by increasing the distance, separate plasma channels are formed, and more filaments are observed. Moreover, the effect of relative beam angle variation reveals that, unexpectedly, two distinct channels formed and traveled through plasma. By increasing the angle to
θ = 2^°, the channels merged and formed a single wide channel. Further, for a constant beams distance, the maximum filaments are observed at the middle angles θ = 4^°, 6^°. It should be noted that studying laser beam filamentation in plasma is so critical for stable pulse propagation through the plasma. Our simulations indicate that in some relative angles, we will not have stable and efficient pulse propagation. This could be distractive in some experiments such as inertial confinement fusion.