Fate of Convection Cells in 2D Yukawa Liquids via Molecular Dynamics Simulations

Convection cells are found in a diverse variety of natural as well as technological systems such as Sun, planetary atmosphere, Earth’s mantle, oceans, tea kettle, Tokamaks etc. In view of their ubiquity, several attempts have been made to understand the stability of convection cells in conventional liquids using 2D hydrodynamic studies [1].

Yukawa liquids, often realized in Complex plasmas, is a unique medium wherein particle-level kinetic data is tractable at all times. Considering the ubiquitous nature of convective cells and the feasilbility of particle-level obervations in Complex plasmas, we investigate the stability of 2D convective cells, initialized in a Yukawa liquid, using classical “first principles” Molecular Dynamics (MD) [2]. It is found that a semi-periodic array of convection cells can give rise to 1D shear flows under certain types of velocity perturbations. The correlations of grains, system’s aspect ratio and neutral-drag forces are found to play important roles in the abovesaid fluid flow transition. This is the first time, a quantitative estimate of fluid Reynolds stress from MD data is unambiguously shown to lead to shear flows via tilting instability. Additionally, the possibility of experimental realization of our findings in basic plasma labs is discussed.