Surface and volume effects in micro-scale plasma evolution

Abstract

Micro-scale plasmas are extremely interesting due to the spectrum of applications potentially feasible for these small scale plasmas. Due to the small physical size and short temporal scales, simulations can provide complementary and insightful tools to help understand the underlying physical processes. The present paper discusses a numerical model coupling the plasma, metastable species and gas dynamics in atmospheric microcavities in helium at atmospheric pressure. The self-consistent and time-dependant model is described with emphasis on terms involved in the close coupling among species (plasma, metastable and gas) and the applied field – both electric and magnetic fields. The microplasmas are studied from an initial cloud and transients are particularly important in the evolution. Gas heating, neutral depletion initiation and electrohydrodynamic effects are observed, highlighting the interaction between neutral gas and plasma species in governing the microplasmas. The crucial effects of the applied magnetic field and secondary emission are discussed – and surface and volume effects are compared in terms of spatial and temporal evolutions of the plasma and gas dynamics in atmospheric microplasmas.