Kinetic modeling of sodium in the lunar exosphere

Tenishev, V.; Rubin, Martin; Tucker, O. J.; Combi, M. R.; Sarantos, M.

doi:10.1016/j.icarus.2013.08.021

Cited by 38 publications

(58 citation statements)

References 111 publications

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“…modeled the soft X-ray intensities produced by charge exchange at the Moon and predicted them to be about 10 keV cm −2 s −1 sr −1 , comparable to the diffuse cosmic X-ray background (Lumb et al 2002). presented observations of limb brightening in the ROSAT lunar data consistent with the expected signal from solar wind charge exchange with the lunar exosphere and compared these observations to the predictions of hybrid simulations for solar wind ion access to regions behind the terminator of the Moon Farrell et al 2008;Fatemi et al 2012) and models of the lunar exosphere (Sarantos et al 2012;Tenishev et al 2013). Of particular note is that the soft X-rays produced by charge exchange can provide diagnostics on the entire neutral exospheric density including all species, whereas other techniques are spectroscopic in nature and observe particular lines, for example Na (Potter et al 2000).…”

Section: The Moonmentioning

confidence: 71%

Imaging Plasma Density Structures in the Soft X-Rays Generated by Solar Wind Charge Exchange with Neutrals

et al. 2018

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Both heliophysics and planetary physics seek to understand the complex nature of the solar wind's interaction with solar system obstacles like Earth's magnetosphere, the ionospheres of Venus and Mars, and comets. Studies with this objective are frequently conducted with the help of single or multipoint in situ electromagnetic field and particle observations, guided by the predictions of both local and global numerical simulations, and placed in con- text by observations from far and extreme ultraviolet (FUV, EUV), hard X-ray, and energetic neutral atom imagers (ENA). Each proposed interaction mechanism (e.g., steady or transient magnetic reconnection, local or global magnetic reconnection, ion pick-up, or the KelvinHelmholtz instability) generates diagnostic plasma density structures. The significance of each mechanism to the overall interaction (as measured in terms of atmospheric/ionospheric loss at comets, Venus, and Mars or global magnetospheric/ionospheric convection at Earth) remains to be determined but can be evaluated on the basis of how often the density signatures that it generates are observed as a function of solar wind conditions. This paper reviews efforts to image the diagnostic plasma density structures in the soft (low energy, 0.1-2.0 keV) X-rays produced when high charge state solar wind ions exchange electrons with the exospheric neutrals surrounding solar system obstacles. The introduction notes that theory, local, and global simulations predict the characteristics of plasma boundaries such the bow shock and magnetopause (including location, density gradient, and motion) and regions such as the magnetosheath (including density and width) as a function of location, solar wind conditions, and the particular mechanism operating. In situ measurements confirm the existence of time-and spatial-dependent plasma density structures like the bow shock, magnetosheath, and magnetopause/ionopause at Venus, Mars, comets, and the Earth. However, in situ measurements rarely suffice to determine the global extent of these density structures or their global variation as a function of solar wind conditions, except in the form of empirical studies based on observations from many different times and solar wind conditions. Remote sensing observations provide global information about auroral ovals (FUV and hard X-ray), the terrestrial plasmasphere (EUV), and the terrestrial ring current (ENA). ENA instruments with low energy thresholds (∼ 1 keV) have recently been used to obtain important information concerning the magnetosheaths of Venus, Mars, and the Earth. Recent technological developments make these magnetosheaths valuable potential targets for high-cadence wide-field-of-view soft X-ray imagers.Section 2 describes proposed dayside interaction mechanisms, including reconnection, the Kelvin-Helmholtz instability, and other processes in greater detail with an emphasis on the plasma density structures that they generate. It focuses upon the questions that remain as yet unanswered, such as the significanc...

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Section: The Moonmentioning

confidence: 71%

Imaging Plasma Density Structures in the Soft X-Rays Generated by Solar Wind Charge Exchange with Neutrals

et al. 2018

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“…The Moon's rotation in a three‐body system results in 1–2° variation of subsolar point (e.g. Tenishev et al, ). However, including such effects would not alter the conclusions of this study.…”

Section: Methodsmentioning

confidence: 99%

Solar Wind Implantation Into the Lunar Regolith: Monte Carlo Simulations of H Retention in a Surface With Defects and the H₂ Exosphere

et al. 2019

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The solar wind implants protons into the top 20–30 nm of lunar regolith grains, and the implanted hydrogen will diffuse out of the regolith but also interact with oxygen in the regolith oxides. We apply a statistical approach to estimate the diffusion of hydrogen in the regolith hindered by forming temporary bonds with regolith oxygen atoms. A Monte Carlo simulation was used to track the temporal evolution of bound OH surface content and the H2 exosphere. The model results are consistent with the interpretation of the Chandrayaan‐1 M3 observations of infrared absorption spectra by surface hydroxyls as discussed in Li and Milliken (2017, https://doi.org/10.1126/sciadv.1701471). The model reproduced the latitudinal concentration of OH by using a Gaussian energy distribution of f(U0 = 0.5 eV, UW = 0.078–0.1 eV) to characterize the activation energy barrier to the diffusion of hydrogen in space weathered regolith. In addition, the model results of the exospheric content of H2 are consistent with observations by the Lyman Alpha Mapping Project on the Lunar Reconnaissance Orbiter. Therefore, we provide support for hydroxyl formation by chemically trapped solar wind protons.

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“…This study was carried out using a new framework that results from the coupling of the Mars Adaptive Mesh Particle Simulator (M‐AMPS) [ Tenishev et al ., , ] and the Mars Global Ionosphere Thermosphere Model (M‐GITM) [ Bougher et al ., ] for the first time for a range of different solar conditions and seasons. M‐AMPS and M‐GITM are one‐way coupled, which means that the Martian hot corona is simulated without the heating feedback from M‐AMPS to M‐GITM in time.…”

Section: Introductionmentioning

confidence: 99%

Hot oxygen corona at Mars and the photochemical escape of oxygen: Improved description of the thermosphere, ionosphere, and exosphere

Lee

Combi

Tenishev

et al. 2015

J. Geophys. Res. Planets

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The Mars Adaptive Mesh Particle Simulator model is coupled with the Mars Global Ionosphere Thermosphere Model for the first time to provide an improved description of the Martian hot O corona based on our modeling studies of O2+ dissociative recombination. A total of 12 cases comprising three solar activity levels and four orbital positions is considered to study the solar cycle and seasonal variability. The newly coupled framework includes two additional thermospheric species and adopts a realistic forward scattering scheme using the angular differential cross sections. We present the effects of these changes on the resulting hot O corona and escape rate. A comparison between the simulated hot O corona and the recent observations from the ALICE/Rosetta instrument showed a reasonable agreement, considering the large uncertainties in the data. We assume that some discrepancies near the transition altitude may be originated from the averaging over the altitude range, where the cold and hot O densities become comparable. The revised O escape rates by our new coupled framework range from ~1.21 × 1025 s−1 to ~5.43 × 1025 s−1.

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Kinetic modeling of sodium in the lunar exosphere

Cited by 38 publications

References 111 publications

Imaging Plasma Density Structures in the Soft X-Rays Generated by Solar Wind Charge Exchange with Neutrals

Imaging Plasma Density Structures in the Soft X-Rays Generated by Solar Wind Charge Exchange with Neutrals

Solar Wind Implantation Into the Lunar Regolith: Monte Carlo Simulations of H Retention in a Surface With Defects and the H₂ Exosphere

Hot oxygen corona at Mars and the photochemical escape of oxygen: Improved description of the thermosphere, ionosphere, and exosphere

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Kinetic modeling of sodium in the lunar exosphere

Cited by 38 publications

References 111 publications

Imaging Plasma Density Structures in the Soft X-Rays Generated by Solar Wind Charge Exchange with Neutrals

Imaging Plasma Density Structures in the Soft X-Rays Generated by Solar Wind Charge Exchange with Neutrals

Solar Wind Implantation Into the Lunar Regolith: Monte Carlo Simulations of H Retention in a Surface With Defects and the H2 Exosphere

Hot oxygen corona at Mars and the photochemical escape of oxygen: Improved description of the thermosphere, ionosphere, and exosphere

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Solar Wind Implantation Into the Lunar Regolith: Monte Carlo Simulations of H Retention in a Surface With Defects and the H₂ Exosphere