Ekoplasma — Experiments with grid electrodes in microgravity

Knapek, Christina A.; Huber, Peter J.; Mohr, Daniel; Zaehringer, Erich; Molotkov, V. I.; Lipaev, A. M.; Naumkin, V. N.; Konopka, Uwe; Thomas, Hubertus M.; Фортов, В. Е.

doi:10.1063/1.5020392

Cited by 13 publications

(21 citation statements)

References 12 publications

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“…Figure 7 illustrates the spallation accessibility for different probe diameters provided that the dust particle diameter and the argon pressure are fixed. As is seen, spallation is impossible as a p → a; this follows straightforwardly from (29) and (30). Spallation is hindered for high electron number density as well because of the associated increase of n d .…”

Section: Spallation Threshold For the Dust Cloudmentioning

confidence: 62%

“…For comparison, Fig. 9 also shows the line Q = 1, where the quantities included in (29) are calculated using the OML-based IEOS [23]. It is seen that the threshold particle number densities are up to three orders of magnitude lower than those calculated in this work.…”

Section: Spallation Threshold For the Dust Cloudmentioning

confidence: 78%

“…In so doing, we will confine ourselves to the case a > a p and assume a quasi-homogeneous dust cloud in the argon discharge. Then the estimation of the length scale L ∼ 5 cm in (29) can be of the same order as typical discharge dimensions. Figure 7 illustrates the spallation accessibility for different probe diameters provided that the dust particle diameter and the argon pressure are fixed.…”

Section: Spallation Threshold For the Dust Cloudmentioning

confidence: 88%

“…From (29) and (30) for |a − a p | /a ∼ 1 and ρ > 3/8, one can obtain a crude estimate Q ≃ r d λ a /aΦL. This means that spallation would be impossible for a dense system (small r d ) of large particles at high argon pressure.…”

Section: Spallation Threshold For the Dust Cloudmentioning

confidence: 99%

“…Proposed IEOS is significant for both understanding the properties of dusty plasmas and planning the future experiments. Thus, based on a standard simulation of the discharge without particles and the developed IEOS, one can estimate the parameters of complex plasma for the Ekoplasma project, which is a Russian-German cooperation building the future laboratory for the investigation of complex plasmas under microgravity conditions on the ISS [29]. Such calculations will enable optimization of the conditions of forthcoming experiments.…”

Section: Introductionmentioning

confidence: 99%

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Ionization equation of state for the dusty plasma including the effect of ion–atom collisions

Zhukhovitskii

2019

Physics of Plasmas

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The ionization equation of state (IEOS) for a cloud of the dust particles in the low-pressure gas discharge under microgravity conditions is proposed. IEOS relates pairs of the parameters specific for the charged components of dusty plasma. It is based on the modified collision enhance collection model adapted for the Wigner-Seitz cell model of the dust cloud. This model takes into account the effect of ion-atom collisions on the ion current to the dust particles and assumes that the screening length for the ion-particle interaction is of the same order of magnitude as the radius of the Wigner-Seitz cell. Included effect leads to a noticeable decrease of the particle charge as compared to the previously developed IEOS based on the orbital motion limited model. Assuming that the Havnes parameter of the dusty plasma is moderate one can reproduce the dust particle number density measured in experiments and, in particular, its dependence on the gas pressure. Although IEOS includes no fitting parameters, it can ensure a satisfactory precision in a wide range of dusty plasma parameters. Based on the developed IEOS, the threshold relation between the dusty plasma parameters for onset of the lane formation in binary dusty plasmas is deduced.

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Section: Spallation Threshold For the Dust Cloudmentioning

confidence: 62%

Section: Spallation Threshold For the Dust Cloudmentioning

confidence: 78%

Section: Spallation Threshold For the Dust Cloudmentioning

confidence: 88%

Section: Spallation Threshold For the Dust Cloudmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Ionization equation of state for the dusty plasma including the effect of ion–atom collisions

Zhukhovitskii

2019

Physics of Plasmas

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Formation of droplets in weightless complex plasmas

Joshi

Khrapak

Knapek

et al. 2021

Contributions to Plasma Physics

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Microparticles immersed in a low-temperature plasma acquire strong negative charges and thus repel each other. Nevertheless, effective attraction between the microparticles in such a complex plasma can occur due to the interplay between the fluxes of plasma ions and the microparticles. Here, we report the observation of droplets formed in a complex plasma during a parabolic flight, and explain their formation in terms of the ion drag force that sustains the droplet. We have found a good agreement between the experimentally determined droplet size and its theoretical estimate using the ion drag force mechanism. Lower values of the electron temperature result in better agreement, as is consistent with the pulsed mechanism of discharge used experimentally.

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Physical aspects of dust–plasma interactions

Pustylnik

Pikalev

Zobnin

et al. 2021

Contributions to Plasma Physics

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Low‐pressure gas discharge plasmas are known to be strongly affected by the presence of small dust particles. This issue plays a role in the investigations of dust particle‐forming plasmas, where the dust‐induced instabilities may affect the properties of synthesized dust particles. Also, gas discharges with large amounts of microparticles are used in microgravity experiments, where strongly coupled subsystems of charged microparticles represent particle‐resolved models of liquids and solids. In this field, deep understanding of dust–plasma interactions is required to construct the discharge configurations which would be able to model the desired generic condensed matter physics as well as, in the interpretation of experiments, to distinguish the plasma phenomena from the generic condensed matter physics phenomena. In this review, we address only physical aspects of dust–plasma interactions, that is, we always imply constant chemical composition of the plasma as well as constant size of the dust particles. We also restrict the review to two discharge types: dc discharge and capacitively coupled rf discharge. We describe the experimental methods used in the investigations of dust–plasma interactions and show the approaches to numerical modelling of the gas discharge plasmas with large amounts of dust. Starting from the basic physical principles governing the dust–plasma interactions, we discuss the state‐of‐the‐art understanding of such complicated, discharge‐type‐specific phenomena as dust‐induced stratification and transverse instability in a dc discharge or void formation and heartbeat instability in an rf discharge.

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Ekoplasma — Experiments with grid electrodes in microgravity

Cited by 13 publications

References 12 publications

Ionization equation of state for the dusty plasma including the effect of ion–atom collisions

Ionization equation of state for the dusty plasma including the effect of ion–atom collisions

Formation of droplets in weightless complex plasmas

Physical aspects of dust–plasma interactions

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