Modeling nanoparticle charge distribution in the afterglow of non-thermal plasmas and comparison with measurements

A modeling approach to investigate the charge distribution of particles exiting flow-through non-thermal plasmas and the afterglow region is presented. Understanding the effect of plasma parameters, diffusivity of charged species, and reaction rate constants in the resulting particle charge distributions is critical to material synthesis and relevant applications. In this work, ion-flux coefficient models developed using Langevin Dynamics based simulations are incorporated into species transport equations for ions, electrons, and charged particles in the afterglow. Charge predictions from the developed models are compared against measured values in stationary, non-thermal plasmas from past PK-4 campaigns. Experiments of Sharma et al. to probe particle charge distributions are modeled using particle-ion collision rate constant models and the calculated charge fractions are compared with measurements. The comparisons reveal that the plasma concentration and gas temperature in the afterglow region critically influence the particle charge and the predictions are generally in qualitative agreement with the measurements.