Computational modeling of a nonlinearly coupled light and particle beam propagation*

Interaction of light and gas particles plays an important role in laser diagnostics, optical tweezers, cold plasmas, and space propulsion. While a collimated light beam naturally diffracts without any guiding media and particles diffuse due to their thermal motion in vacuum, precisely tailoring the coupling of the two can lead to mutually self-guided beams. A self-consistent computational model for co-propagation of light and particle beams has been developed and validated against experimental results from relevant literature. While the previous studies have focused on the trapping of particles due to optical forces, we investigate and quantify the mutual guiding (i.e., particle trapping and light guiding) effects using our computational model. We further employ our model to gain insight into the opportunities and limitations of employing a coupled light-particle beam as a space propulsion system. The influence of several relevant parameters such as particle density, temperature, laser beam waist, and power on effective particle trapping and waveguiding is explored.