Dust particles of finite dimensions in complex plasmas: thermodynamics and dust-acoustic wave dispersion

Abstract

Grounded on the premise that dust particles are charged hard balls, the analysis in Davletov et al. (Contrib. Plasma Phys., vol. 56, 2016, 308) provides an original pseudopotential model of intergrain interaction in complex (dusty) plasmas. This accurate model is engaged herein to consistently treat the finite-size effects from the process of dust particle charging to determination of the thermodynamic quantities and the dust-acoustic wave dispersion in the strongly coupled regime. The orbital motion limited approximation is adopted to evaluate an electric charge of dust grains immersed in a neutralizing background of the buffer plasma. To account for finite dimensions of dust particles, the radial distribution function is calculated within the reference hypernetted-chain (RHNC) approximation to demonstrate a well-pronounced short-range order formation at rather large values of the coupling parameter and the packing fraction. The evaluated excess pressure of the dust component is compared to the available theoretical approaches and the simulation data and is then used to predict the dust-acoustic wave (DAW) dispersion in the strongly coupled regime under the assumption that the dust particles charge varies in the course of propagation. In contrast to many previous investigations, it is demonstrated for the first time ever that for DAWs the charge variation of dust particles should necessarily be taken into account while evaluating the dust isothermal compressibility.

DPEx-II: a new dusty plasma device capable of producing large sized DC coulomb crystals

“…It is due to the fact that the particles levitate in the sheath of the bottom electrode in a parallel plate configuration having small plasma volume. The size of the crystal, with a smaller number of particles (a few tens to few hundreds) is good enough to study the dynamics of particles at an individual level [24]. However, for exploring the thermodynamics of Coulomb crystal, the number of dust particles has to be as large as possible to minimize the error associated with the statistical fluctuation (∝ 1 √ N , where N is the number of particles) [25].…”

Volumetric measurement of the synchronization and desynchronization of the dust acoustic wave with an external modulation

“…2009; Williams & Snipes 2010; Ruhunusiri & Goree 2014; Avinash 2015; Davletov et al. 2018) of this wave mode, wave breaking (Liao et al. 2008; Teng et al.…”

“…This allows for the study of the properties of the dust-related phenomena such as the dust acoustic wave mode at both the global and individual particle level with incredible spatial and temporal resolution (Killer & Melzer 2014;Tadsen et al 2015;Tadsen, Greiner & Piel 2017;Yaroshenko et al 2019). In recent years, this has allowed for the study of a wide range of the properties this wave mode, including wave-particle interactions (Liao et al 2008;Chang, Teng & Lin 2012), the growth (Thomas 2006;Flanagan & Goree 2011;Heinrich et al 2011;Williams 2013) and dispersion relation (Trottenberg, Block & Piel 2006;Thomas, Fisher & Merlino 2007;Rosenberg, Thomas & Merlino 2008;Nosenko et al 2009;Williams & Snipes 2010;Ruhunusiri & Goree 2014;Avinash 2015;Davletov et al 2018) of this wave mode, wave breaking (Liao et al 2008;Teng et al 2009) and turbulence (Tsai, Chang & Lin 2014). Further, the majority of the experimental observations that have been made of this wave mode in the laboratory setting involve waves that are nonlinear (Merlino 2012).…”

Dynamic properties of strongly coupled dusty plasmas with particles of finite dimensions

“…First of all, it is evident that in a strongly coupled dusty plasma the electrostatic force between dust particles dominates in comparison with other contributions to interaction, such as the ion drag force, etc. The other reason is that the dust component should only slightly affect the ionization equilibrium in the surrounding plasma, otherwise it is necessary to take into account the charge variation of dust particles by incorporating into consideration the electron and ion dynamics . In the present research, those assumptions are presumed to be simultaneously fulfilled in order to focus all attention on the influence the finiteness of dust particles dimensions has on their collective dynamic properties, which particularly include the dynamic structure factor and the spectrum of dust‐acoustic waves.…”