Ion emission from micrometeorite impacts on atmosphereless planets

Wekhof, A.

doi:10.1007/bf00898429

Cited by 4 publications

(3 citation statements)

References 6 publications

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“…Figure shows upper limits derived on the micrometeoroid bombardment‐induced pickup ion flux as a function of the incoming distribution, ranging from approximately 10 5 cm −2 s −1 to 10 7 cm −2 s −1 as the distribution shifts from isotropic to peaked at the dawn terminator. As discussed earlier, the most likely distribution at the Moon is approximately the cos θ with a 60° degree offset [ Janches et al ., ], for an upper limit of approximately 10 6 cm −2 s −1 , significantly higher than that theoretically estimated [ Wekhof , , ]. Nevertheless, these constraints are, to our knowledge, the first reported from in situ.…”

Section: Exospheric Constraintssupporting

confidence: 88%

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Model‐based constraints on the lunar exosphere derived from ARTEMIS pickup ion observations in the terrestrial magnetotail

et al. 2013

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[1] We use Acceleration, Reconnection, Turbulence and Electrodynamics of the Moon's Interaction with the Sun (ARTEMIS) measurements of lunar exospheric pickup ions in the terrestrial magnetotail lobes combined with a particle-tracing model to constrain the source species and distributions of the lunar neutral exosphere. These pickup ions, generated by photoionization of neutral species while the Moon is in the magnetotail lobes, undergo acceleration from both the magnetotail convection electric field and the lunar surface photoelectric field, giving rise to distinct pickup ion flux, pitch angle, and energy distributions. By simulating the behavior of lunar pickup ions in the magnetotail lobes and the response of the twin ARTEMIS probes under various ambient conditions, we can constrain several physical quantities associated with these observations, including the source ion production rate and the magnetotail convection velocity (and hence, electric field). Using the model-derived source ion production rate and established photoionization rates, we present upper limits on the density of several species potentially in the lunar exosphere. In certain cases, these limits are lower than those previously reported. We also present evidence that the lunar exosphere is displaced toward the lunar dawnside while in the terrestrial magnetotail based on fits to the observed pickup ion distributions.Citation: Poppe, A. R., J. S. Halekas, R. Samad, M. Sarantos, and G. T. Delory (2013), Model-based constraints on the lunar exosphere derived from ARTEMIS pickup ion observations in the terrestrial magnetotail,

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Section: Exospheric Constraintssupporting

confidence: 88%

“…As an additional exercise, we can use the model to address ions produced directly at the lunar surface via micrometeoroid bombardment [ Wekhof , ]. To this end, we ran the model under identical convection parameters as above with ions generated across the dayside directly at the lunar surface.…”

Section: Exospheric Constraintsmentioning

confidence: 99%

Model‐based constraints on the lunar exosphere derived from ARTEMIS pickup ion observations in the terrestrial magnetotail

et al. 2013

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“…Negative ions are expected to make up a small fraction (1–10%) of the ionized material in the lunar exosphere, formed mainly by the interaction of solar wind protons with the lunar regolith (“topsoil”) or by micrometeorite impacts on the surface [ Wekhof , , ]. A larger fraction is expected near shaded regions or on the nightside of the Moon, where the surface becomes negatively charged and expels negatively charged dust and plasma [ Farrell et al ., ].…”

Section: Measurement Objectivesmentioning

confidence: 99%

Detecting negative ions on board small satellites

et al. 2017

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Recent measurements near comets, planets, and their satellites have shown that heavy ions, energetic neutral atoms, molecular ions, and charged dust contain a wealth of information about the origin, evolution, and interaction of celestial bodies with their space environment. Using highly sensitive plasma instruments, positively charged heavy ions have been used to trace exospheric and surface composition of comets, planets, and satellites as well as the composition of interplanetary and interstellar dust. While positive ions dominate throughout the heliosphere, negative ions are also produced from surface interactions. In fact, laboratory experiments have shown that oxygen released from rocky surfaces is mostly negatively charged. Negative ions and negatively charged nanograins have been detected with plasma electron analyzers in several different environments (e.g., by Cassini and Rosetta), though more extensive studies have been challenging without instrumentation dedicated to negative ions. We discuss an adaptation of the Fast Imaging Plasma Spectrometer (FIPS) flown on MErcury Surface, Space ENvironment, GEochemistry and Ranging (MESSENGER) for the measurement of negatively charged particles. MESSENGER/FIPS successfully measured the plasma environment of Mercury from 2011 until 2015, when the mission ended, and has been used to map multiple ion species (H+ through Na+ and beyond) throughout Mercury's space environment. Modifications to the existing instrument design fits within a 3U CubeSat volume and would provide a low mass, low power instrument, ideal for future CubeSat or distributed sensor missions seeking, for the first time, to characterize the contribution of negative particles in the heliospheric plasmas near the planets, moons, comets, and other sources.

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Negative ions in the ionospheres of planetary bodies without atmospheres

Wekhof

1981

The Moon and the Planets

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Ion emission from micrometeorite impacts on atmosphereless planets

Cited by 4 publications

References 6 publications

Model‐based constraints on the lunar exosphere derived from ARTEMIS pickup ion observations in the terrestrial magnetotail

Model‐based constraints on the lunar exosphere derived from ARTEMIS pickup ion observations in the terrestrial magnetotail

Detecting negative ions on board small satellites

Negative ions in the ionospheres of planetary bodies without atmospheres

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