Suppression of the ion drag force on dust in magnetized plasmas

James, Lloyd; Coppins, M.

doi:10.1063/5.0004584

Cited by 3 publications

(2 citation statements)

References 34 publications

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“…From recent simulations and accompanying calculations it is found that the gyro motion of magnetized ions results in a reduced momentum transfer from the ions to the dust. Hence, the ion drag force becomes more and more suppressed by the actions of a magnetic field (James and Coppins 2020). However, this effect seems to become important only when the ion gyro radius is of the order of the particle radius (for a 10 micron dust particle this requires a magnetic field of about 10 T).…”

Section: Forcesmentioning

confidence: 99%

Physics of magnetized dusty plasmas

Melzer¹,

Krüger²,

Maier³

et al. 2021

Rev. Mod. Plasma Phys.

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In this review, we summarize recent advances in the field of dusty plasmas at strong magnetic fields. Special emphasis is put on situations where experimental laboratory observations are available. These generally comprise dusty plasmas with magnetized electrons and ions, but unmagnetized dust. The fundamental parameters characterizing a magnetized (dusty) plasma are given and various effects in dusty plasmas under magnetic fields are presented. As examples, the reaction of the dust component to magnetic-field modified plasma properties, such as filamentation, imposed structures, dust rotation, nanodusty plasmas and the resulting forces on the dust are discussed. Further, the behavior of the dust charge is described and shown to be relatively unaffected by magnetic fields. Wake field formation in magnetized discharges is illustrated: the strength of the wake field is found to be reduced with increased magnetic field. The propagation of dust acoustic waves in magnetized dusty plasmas is experimentally measured and analyzed indicating that the wave dynamics are not heavily influenced by the magnetic field. Only at the highest fields ($$B> 1$$ B > 1 T) the wave activity is found to be reduced. Moreover, it is discussed how dust-cyclotron waves might be used to indicate a magnetized dust component. Finally, implications of a magnetized dusty plasma are illustrated.

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Section: Forcesmentioning

confidence: 99%

Physics of magnetized dusty plasmas

Melzer¹,

Krüger²,

Maier³

et al. 2021

Rev. Mod. Plasma Phys.

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“…In Ref. [36], numerical simulations of ion drag force on a dust grain in magnetized plasma are performed. The authors find that magnetization reduces the drag force, but it remains substantially unvaried for a d /ρ L < 0.1.…”

Section: Scaling Of Turbulent Spreadingmentioning

confidence: 99%

Hyperdiffusion of dust particles in a turbulent tokamak plasma

et al. 2021

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The effect of plasma turbulence on the trajectories of dust particles is investigated for the first time. The dynamics of dust particles is computed using the ad-hoc developed Dust Injection Simulator code, using a 3D turbulent plasma background computed with the TOKAM3X code. As a result, the evolution of the particle trajectories is governed by the ion drag force, and the shape of the trajectory is set by the Stokes number St ∝ a d /n 0 , with a d the dust radius and n 0 the density at the separatrix. The plasma turbulence is observed to scatter the dust particles, exhibiting a hyperdiffusive regime in all cases. The amplitude of the turbulent spread of the trajectories ∆r 2 is shown to depend on the ratio Ku/St, with Ku ∝ u rms the Kubo number and u rms the fluctuation level of the plasma flow. These results are compared with a simple analytical model, predicting ∆r 2 ∝ (Ku/St) 2 t 3 , or ∆r 2 ∝ (u rms n 0 /a d ) 2 t 3 . As the dust is heated by the plasma fluxes, thermionic emission sets the dust charge, originally negative, to slightly positive values. This results in a substantial reduction of the ion drag force through the suppression of its Coulomb scattering component. The dust grain inertia is then no longer negligible, and drives the transition from a hyperdiffusive regime towards a ballistic one.

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Physics and applications of dusty plasmas: The Perspectives 2023

Beckers,

Berndt,

Block

et al. 2023

Physics of Plasmas

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Dusty plasmas are electrically quasi-neutral media that, along with electrons, ions, neutral gas, radiation, and electric and/or magnetic fields, also contain solid or liquid particles with sizes ranging from a few nanometers to a few micrometers. These media can be found in many natural environments as well as in various laboratory setups and industrial applications. As a separate branch of plasma physics, the field of dusty plasma physics was born in the beginning of 1990s at the intersection of the interests of the communities investigating astrophysical and technological plasmas. An additional boost to the development of the field was given by the discovery of plasma crystals leading to a series of microgravity experiments of which the purpose was to investigate generic phenomena in condensed matter physics using strongly coupled complex (dusty) plasmas as model systems. Finally, the field has gained an increasing amount of attention due to its inevitable connection to the development of novel applications ranging from the synthesis of functional nanoparticles to nuclear fusion and from particle sensing and diagnostics to nano-contamination control. The purpose of the present perspectives paper is to identify promising new developments and research directions for the field. As such, dusty plasmas are considered in their entire variety: from classical low-pressure noble-gas dusty discharges to atmospheric pressure plasmas with aerosols and from rarefied astrophysical plasmas to dense plasmas in nuclear fusion devices. Both fundamental and application aspects are covered.

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Suppression of the ion drag force on dust in magnetized plasmas

Cited by 3 publications

References 34 publications

Physics of magnetized dusty plasmas

Physics of magnetized dusty plasmas

Hyperdiffusion of dust particles in a turbulent tokamak plasma

Physics and applications of dusty plasmas: The Perspectives 2023

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