Appendix

As illustrated in Fig.5, an anomalous reduction in the large-angle atomic deposition on the collector plate is evident under conditions of high evaporation rate, as indicated by the magenta solid line. In order to elucidate this phenomenon, a comparative analysis of the macroscopic physical parameter distributions for gadolinium atomic vapor was performed via simulation at source temperatures of 1600 K and 2200 K. Relevant results is presented in Fig.9 which comprises subfigures showing the atomic number density (in unit of m-3), velocity in the x-direction (in unit of m/s), velocity in the z-direction (in unit of m/s), and ‘temperature’ (in unit of Kelvin). The left panel corresponds to the 1600 K case and the right panel to the 2200 K case in each subfigure. It is evident that in subfigure (a), the number density for the 1600 K case is displayed at 1000 times its actual simulated value to enable a clear comparison using a unified color bar, as its true magnitude is substantially lower than that at 2200 K. The results from subfigures (c) and (d) demonstrate that the atomic vapor beam generated at the higher evaporation rate (2200 K) possesses a significantly greater z-direction velocity, a lower “temperature”, which means a smaller velocity divergence. This finding indicates that the synergistic effect of intense interatomic collisions, in conjunction with the constrained beam-forming structure, promotes the formation of a low-temperature, directed atomic jet from the high-density vapor.

Fig. 9. Distributions of gadolinium macroscopic parameters at Ts = 1600 K and Ts = 2200 K. (a). atomic density, (b). x-direction velocity, (c). z-direction velocity and (d). ‘temperature’.