Convection in a dusty radio-frequency plasma under the influence of a thermal gradient

Abstract

Gas convection is a common phenomenon in systems under atmospheric pressure conditions with a temperature gradient. Under low pressure conditions, convection can be induced by creep flows along a surface. This has important applications in fluid physics as well as in low pressure plasmas in which a temperature gradient is present. Here, we visualize the gas dynamics in a system with and without a plasma using microparticles as tracers. Two types of gas convection have been identified from the particle motion, i.e. free (Rayleigh–Bénard) convection at high gas pressures, and convection induced by thermal creep at low pressures. The gas flow profile detected using the microparticles is compared with that obtained in a simulation using the direct simulation Monte Carlo method.