Dust as a Gas Carrier

Beránek, M.; Vysinka, Marek; Pavlu, Jiri; Richterová, I.; Němeček, Zdenek; Šafránková, Jana

doi:10.1109/tps.2009.2038219

Cited by 4 publications

(7 citation statements)

References 24 publications

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“…An additional heating by the ion impact and a cooling through the ion desorption are negligible. A detailed analysis made in [16] has shown that the two mentioned processes result in a grain temperature of about 350 K. We can point out that the heat flow in our experiment is similar to that expected approximately at the Venus orbit. On the other hand, both ion bombardment and ion desorption can be important for the grain heat balance in the interstellar space where the radiation power is low.…”

Section: Discussion Of Resultssupporting

confidence: 84%

“…The time constant determined by Beránek et al [16] from the changes of the grain mass after treatment would be a combination of both processes, and it lies between two aforementioned values as can be expected. The aforementioned explanation is very simplified because both processes act simultaneously and only a comprehensive model that takes into account temporal changes of the spatial profile of the density inside the grain during the treatment as well as in the course of the consecutive discharging can explain the observed phenomena quantitatively.…”

Section: Discussion Of Resultsmentioning

confidence: 61%

“…On the other hand, the measurements of Beránek et al [16] revealed a relative increase of the 2-μm carbon grain mass by a factor of about 1.5 · 10 −3 after 8 h of the grain bombardment with 7-keV Ar ions. For this reason, we repeated the experiment of Jeřáb et al [11] using carbon grains and Ar ions.…”

Section: Results Of Measurementsmentioning

confidence: 93%

“…The diffusion and the consecutive desorption (1) and (2), and their sum is denoted as (3) in accordance with the numbering of the corresponding equations in the paper. of the Ar ions implanted into the carbon dust grains were measured by Beránek et al [16]. The time constant was determined from a temporal evolution of the grain weight after treatment as d = 7.21 h in their experiment.…”

Section: Discussion Of Resultsmentioning

confidence: 99%

See 3 more Smart Citations

Relation of Charging History to Field Ion Emission From Gold and Carbon Dust

Jerab

Vaverka

Vysinka

et al. 2010

IEEE Trans. Plasma Sci.

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A study of dust-grain charging plays a very important role in the understanding of complex (dusty) plasma. The dust grains are charged by several different processes (e.g., electron and ion attachments, secondary electron emission, photoemission, and field electron and ion emissions), and their charge significantly influences the surrounding plasma. Our laboratory experiment based on an electrodynamic quadrupole trap allows us to investigate some of these processes on a single isolated dust grain which can be trapped and influenced with different agents for a very long time (days). In this paper, we focused on the determination of the relation between charging conditions and the field-emission mechanism because this emission limits positive charges that dust grains can acquire due to photoemission, secondary emission, or ion attachment. The field-ion-emission process is based on the field ionization of the atoms that crosses a critical distance from the grain surface. We have found that the sources of these atoms are either the surrounding gas or the ions implanted into the grain and leaving it due to diffusion. The diffusion can be described by two time constants differing by an order of magnitude. We used two sets of dust grains: gold and amorphous carbon. The experimental results are confirmed by a simple model. Index Terms-Diffusion in solids, dust charging, field ion emission (FIE).

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Section: Discussion Of Resultssupporting

confidence: 84%

Section: Discussion Of Resultsmentioning

confidence: 61%

Section: Results Of Measurementsmentioning

confidence: 93%

Section: Discussion Of Resultsmentioning

confidence: 99%

See 2 more Smart Citations

Relation of Charging History to Field Ion Emission From Gold and Carbon Dust

Jerab

Vaverka

Vysinka

et al. 2010

IEEE Trans. Plasma Sci.

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“…A simple estimation using a black body approximation would lead to several degrees of the grain temperature increase. A more precise estimation of a heat balance under very similar conditions made in [34] led to the grain temperature increase by 30 K. It means that the observed increase in the yield when the positive grain charge is compensated for by the electron beam cannot be connected with the increase in the grain temperature.…”

Section: B Sputtering Yieldmentioning

confidence: 86%

Sputtering of Spherical SiO₂Samples

Vysinka

Němeček

Šafránková

et al. 2016

IEEE Trans. Plasma Sci.

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Dust grains in the interplanetary environment can be basically found in two locations-floating in the free space or attached to a surface of asteroids, comets, or moons. They are sputtered by the impacts of energetic ions, and this process supplies the interplanetary space with heavy elements. The sputtering yield is generally estimated on the basis of laboratory investigations of planar samples. We use silica micrometersized spherical grains as a prototype of a space-borne dust, bombard them by 2-keV Ar ions, and monitor the influences of simultaneous application of the electron beam as well as the electric field at the dust surface on the sputtering yield. We found that the increase in the sputtering yield due to the electron impact is much larger than expected and it can enhance the sputtering yield by a factor of 1.6 in a comparison with the sole ion bombardment. On the other hand, the influence of the electric field is not so strong (if any) and it is masked by electron impacts in our experiment. Sputtering of the grains fixed at a surface by 30-keV Ga ions revealed that the angular profile of the yield is flatter than that frequently used for a description of the sputtering process. Finally, we compare these results with the published sputtering yield values.

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Secondary electron emission from Martian soil simulant

et al. 2014

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In the recent years, growing interest in dust charging physics is connected with several lander missions running on or planned to the Moon, Mars, and Mercury for a near future. In support of these missions, laboratory simulations are a potential tool to optimize in situ exploration and measurements. In the paper, we have investigated electrical properties of a Martian soil simulant prepared at the Johnson Space Center under name JSC Mars‐1 using the dust charging experiment when a single dust grain is trapped in a vacuum chamber and its secondary electron emission is studied. The exposure of the grain to the electron beam revealed that the grain surface potential is low and generally determined by a mean atomic number of the grain material at a low‐energy range (<1 keV), whereas it can reach a limit of the field ion emission being irradiated by more energetic electrons. A comparison of model and experimental results reveals an influence of the grain shape and size predominantly in the range of higher (>2 keV) electron energies. We discuss possible implications of the secondary electron emission for the presence of lightnings on Mars.

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Dust as a Gas Carrier

Cited by 4 publications

References 24 publications

Relation of Charging History to Field Ion Emission From Gold and Carbon Dust

Relation of Charging History to Field Ion Emission From Gold and Carbon Dust

Sputtering of Spherical SiO₂Samples

Secondary electron emission from Martian soil simulant

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Dust as a Gas Carrier

Cited by 4 publications

References 24 publications

Relation of Charging History to Field Ion Emission From Gold and Carbon Dust

Relation of Charging History to Field Ion Emission From Gold and Carbon Dust

Sputtering of Spherical SiO2Samples

Secondary electron emission from Martian soil simulant

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Sputtering of Spherical SiO₂Samples