Secondary Emission From Non-Spherical Dust Grains With Rough Surfaces: Application to Lunar Dust

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

doi:10.1088/0004-637x/761/2/108

Cited by 12 publications

(10 citation statements)

References 25 publications

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“…Similarly, the potential measured above a silica dust covered surface showed ~14 V more negative than that above a smooth, solid silica surface in an identical plasma condition. The reduced SE emission yield for the dusty surface is therefore not due to different surface materials in the above experiments, rather should be mainly attributed to the re‐absorption of the emitted SEs by neighboring dust particles or structures [ Wang et al ., ; Martin and von Engel , ; Wiese et al ., ; Richterová et al ., ; Ma et al ., ]. This mechanism supports our patched charge model and should be also true for photoelectrons emitted from dusty surfaces.…”

Section: Resultsmentioning

confidence: 91%

Dust charging and transport on airless planetary bodies

Wang

Schwan

Hsu

et al. 2016

Geophysical Research Letters

171

167

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We report on laboratory experiments to shed light on dust charging and transport that have been suggested to explain a variety of unusual phenomena on the surfaces of airless planetary bodies. We have recorded micron‐sized insulating dust particles jumping to several centimeters high with an initial speed of ~0.6 m/s under ultraviolet illumination or exposure to plasmas, resulting in an equivalent height of ~0.11 m on the lunar surface that is comparable to the height of the so‐called lunar horizon glow. Lofted large aggregates and surface mobilization are related to many space observations. We experimentally show that the emission and re‐absorption of photoelectron and/or secondary electron at the walls of microcavities formed between neighboring dust particles below the surface are responsible for generating unexpectedly large negative charges and intense particle‐particle repulsive forces to mobilize and lift off dust particles.

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Section: Resultsmentioning

confidence: 91%

Dust charging and transport on airless planetary bodies

Wang

Schwan

Hsu

et al. 2016

Geophysical Research Letters

171

167

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“…The model calculations in Richterová et al [] are based on an assumption of the spherical symmetry; thus, it does not allow us to check directly the hypothesis of a nonspherical shape of the grain. For this reason, we have changed the coordinate system used in the model and applied a new modification that includes a nonspherical shape of grains (see Richterova et al [] for a detailed description). Figure presents calculated potentials of cuboids from SiO 2 .…”

Section: Resultsmentioning

confidence: 99%

“…Surface potentials of cuboids from SiO 2 calculated according to Richterova et al []. See text for a detailed description.…”

Section: Resultsmentioning

confidence: 99%

“…A comparison of the Maxwellian and Draine and Salpeter distributions is shown in Figure together with experimental points derived from measurements on a 1 μm SiO 2 sphere. These points were obtained from measurements of the surface potential profile similar to that described in the previous section under assumptions of the validity of the Richterova et al [] model. One can note that neither Maxwell (Figure , red) nor Draine and Salpeter (Figure , blue) distributions match the data in the full energy range.…”

Section: Resultsmentioning

confidence: 99%

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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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“…. This is likely due to the surface roughness that can re-absorb the emitted electrons 20,29,30,31,32,33 .…”

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confidence: 99%

Experimental Methods of Dust Charging and Mobilization on Surfaces with Exposure to Ultraviolet Radiation or Plasmas

Wang

Schwan

Hood

et al. 2018

JoVE

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Electrostatic dust transport has been hypothesized to explain a number of observations of unusual planetary phenomena. Here, it is demonstrated using three recently developed experiments in which dust particles are exposed to thermal plasma with beam electrons, beam electrons only, or ultraviolet (UV) radiation only. The UV light source has a narrow bandwidth in wavelength centered at 172 nm. The beam electrons with the energy of 120 eV are created with a negatively biased hot filament. When the vacuum chamber is filled with the argon gas, a thermal plasma is created in addition to the electron beam. Insulating dust particles of a few tens of microns in diameter are used in the experiments. Dust particles are recorded to be lofted to a height up to a few centimeters with a launch speed up to 1 m/s. These experiments demonstrate that photo and/or secondary electron emission from a dusty surface changes the charging mechanism of dust particles. According to the recently developed "patched charge model", the emitted electrons can be re-absorbed inside microcavities between neighboring dust particles below the surface, causing the accumulation of enhanced negative charges on the surrounding dust particles. The repulsive forces between these negatively charged particles may be large enough to mobilize and lift them off the surface. These experiments present the advanced understanding of dust charging and transport on dusty surfaces, and laid a foundation for future investigations of its role in the surface evolution of airless planetary bodies.

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Secondary Emission From Non-Spherical Dust Grains With Rough Surfaces: Application to Lunar Dust

Cited by 12 publications

References 25 publications

Dust charging and transport on airless planetary bodies

Dust charging and transport on airless planetary bodies

Secondary electron emission from Martian soil simulant

Experimental Methods of Dust Charging and Mobilization on Surfaces with Exposure to Ultraviolet Radiation or Plasmas

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