Mapping chemical reaction pathways in discharge plasmas: An approach based on force-directed layout

In the exploration of humid air discharges at atmospheric pressure using chemical kinetics, the mapping of chemical reaction pathways emerges as a crucial instrument for deciphering the underlying mechanisms of the reaction system. In this study, we employed a force-directed layout method to create diagrams of chemical reaction pathways based on simulation results from a global model of humid air discharges at atmospheric pressure. This innovative approach aids in addressing the challenges traditionally associated with mapping these pathways, notably the difficulty in balancing intuitiveness with the precise representation of physical data. In our method, the mass of each node in the diagram is determined by the species density, and the natural length between nodes is defined according to reaction rates, with the forces acting upon the nodes dictated by the variance between the actual distance and this natural length. The final arrangement of the nodes is established upon reaching a stable equilibrium after undergoing damped motion in response to these forces. This methodology not only provides a tangible and intuitive visualization of the complex interactions within discharge plasmas but also enables a detailed sensitivity analysis to assess the significance of various reactions.