Stability of two-dimensional complex plasma monolayers in asymmetric capacitively-coupled radio-frequency discharges
| Autor: | L. Couëdel, V. Nosenko |
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| Přispěvatelé: | Physique des interactions ioniques et moléculaires (PIIM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), University of Saskatchewan [Saskatoon] (U of S), Deutsches Zentrum für Luft- und Raumfahrt [Oberpfaffenhofen-Wessling] (DLR) |
| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: | |
| Popis: | In this article, the stability of a complex plasma monolayer levitating in the sheath of the poweredelectrode of an asymmetric capacitively coupled radio-frequency argon discharge is studied. Com-pared to earlier studies, a better integration of the experimental results and theory is achieved byoperating with actual experimental control parameters such as the gas pressure and the dischargepower. It is shown that for a given microparticle monolayer at a fixed discharge power there existtwo threshold pressures: (i) above a specific pressure p cryst , the monolayer always crystallises; (ii)below a specific pressure p MCI , the crystalline monolayer undergoes the mode-coupling instability andthe two-dimensional complex plasma crystal melts. In-between p MCI and p cryst , the microparticlemonolayer can be either in the fluid phase or the crystal phase: when increasing the pressure frombelow p MCI , the monolayer remains in the fluid phase until it reaches p cryst at which it recrystallises;when decreasing the pressure from above p cryst , the monolayer remains in the crystalline phase untilit reaches p MCI at which the mode-coupling instability is triggered and the crystal melts. A simpleself-consistent sheath model is used to calculate the rf sheath profile, the microparticle charges and themicroparticle resonance frequency as a function of power and background argon pressure. Combinedwith calculation of the lattice modes the main trends of p MCI as a function of power and backgroundargon pressure are recovered. The threshold of the mode-coupling instability in the crystalline phaseis dominated by the crossing of the longitudinal in-plane lattice mode and the out-of plane latticemode induced by the change of the sheath profile. Ion wakes are shown to have a significant effecttoo. Comment: Submitted to Phys. Rev. E |
| Databáze: | OpenAIRE |
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