Exospheres and Energetic Neutral Atoms of Mars, Venus and Titan

Futaana, Yoshifumi; Chaufray, Jean‐Yves; Smith, H. T.; Garnier, Philippe; Lichtenegger, Herbert; Delva, M.; Gröller, H.; Mura, A.

doi:10.1007/s11214-011-9834-4

Cited by 27 publications

(13 citation statements)

References 236 publications

(360 reference statements)

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“…No oxygen ENAs are expected within this range, because it would require unrealistically high energy of the parent oxygen ions (>5 keV) in the region of the high neutral density Futaana et al, 2011]. In addition, no oxygen ENAs have been clearly identified from Mars [Galli et al, 2006].…”

Section: Instrumentation and Data Selectionmentioning

confidence: 94%

“…We choose the TOF (energy) range from 100 to 309 ns (0.3-3 keV) to calculate the flux of hydrogen ENAs as in Grigoriev et al [2006], because almost all hydrogen ENAs are within this range [e.g., Mura et al, 2008;Futaana et al, 2011]. No oxygen ENAs are expected within this range, because it would require unrealistically high energy of the parent oxygen ions (>5 keV) in the region of the high neutral density Futaana et al, 2011]. In addition, no oxygen ENAs have been clearly identified from Mars [Galli et al, 2006].…”

Section: Instrumentation and Data Selectionmentioning

confidence: 99%

“…Futaana et al, 2011]. ENAs preserve the velocities of their parent ions and thus can be used to diagnose the plasma remotely because the ENA production rate is proportional to the product of the ion flux and the neutral particle density.…”

Section: Introductionmentioning

confidence: 99%

“…Energetic neutral atoms (ENAs) are mainly generated via charge exchange reactions between ions and neutral particles in a background neutral gas [cf. Futaana et al, 2011]. ENAs preserve the velocities of their parent ions and thus can be used to diagnose the plasma remotely because the ENA production rate is proportional to the product of the ion flux and the neutral particle density.…”

Section: Introductionmentioning

confidence: 99%

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Influence of Martian crustal magnetic anomalies on the emission of energetic neutral hydrogen atoms

et al. 2014

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We analyze the data on hydrogen energetic neutral atoms (ENAs) emissions from the dayside of Mars, recorded by a Neutral Particle Detector of the Analyzer of Space Plasmas and Energetic Atoms aboard Mars Express from 14 March to 9 July 2004. We first identify and analyze events of the ENA flux enhancement coinciding with the presence of the crustal magnetic anomalies on the dayside of Mars. We then backtrace the ENA emissions to the lower altitudes (source region) and build up an average map of the flux intensities in the geographic coordinates with all the available data. The map shows a peak-to-valley ENA flux enhancement of 40%-90% close to the crustal magnetic anomaly regions. These results suggest the influence of the magnetic anomalies on the ENA emission from the dayside of Mars. The enhancement may result from the deviation of the highly directional plasma flow above anomalies toward the detectors such that more charge exchange ENAs would be recorded. Alternatively, higher exospheric densities above the anomalies would also result in an increase of the charge exchange ENA flux.

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Section: Instrumentation and Data Selectionmentioning

confidence: 94%

Section: Instrumentation and Data Selectionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Influence of Martian crustal magnetic anomalies on the emission of energetic neutral hydrogen atoms

et al. 2014

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“…Other sources of hot neutral oxygen such as sputtering, due to the precipitation of accelerated pick-up O + ions into the Martian atmosphere, are less important in current conditions (Chaufray et al 2007) but could have played a more important role in the past (Leblanc and Johnson 2001;Johnson et al 2008). Moreover, recent detections of energetic neutral atoms (ENAs) produced by charge exchange between energetic ions and the neutral exosphere require accurate coupling between the neutral exosphere and solar wind (Futaana et al 2011). It is therefore important to couple an exospheric model to a plasma model to accurately describe processes related to the solar wind interaction but also to study the effect of pick-up ions precipitation into the Martian upper atmosphere and the additional escape produced by sputtering.…”

Section: The Neutral Exosphere Of Marsmentioning

confidence: 99%

Modeling of Venus, Mars, and Titan

et al. 2011

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Increased computer capacity has made it possible to model the global plasma and neutral dynamics near Venus, Mars and Saturn's moon Titan. The plasma interactions at Venus, Mars, and Titan are similar because each possess a substantial atmosphere but lacks a global internally generated magnetic field. In this article three self-consistent plasma models are described: the magnetohydrodynamic (MHD) model, the hybrid model and the fully kinetic plasma model. are also described. In particular, we describe the pros and cons of each model approach. Results from simulations are presented to demonstrate the ability of the models to capture the known plasma and neutral dynamics near the three objects.

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Directionality and variability of energetic neutral hydrogen fluxes observed by Mars Express

et al. 2013

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[1] Using data collected by the neutral particle detector of the analyzer of space plasmas and energetic atoms on board Mars Express, we establish the global morphology of hydrogen energetic neutral atom (ENA) fluxes. The observations were conducted in March-July 2004 and reveal that low flux ENAs (< 5 10 5 cm -2 s -1 sr -1 ) are emitted roughly isotropically from the dayside of the planet. These ENA emissions originate from the backscattering of the hydrogen ENAs produced by the charge exchange of the upstream solar wind in the extended Martian exosphere. ENAs of higher fluxes are emitted preferentially in the directions perpendicular to the undisturbed solar wind velocity. This population is due to the charge exchange of the magnetosheath plasma. At a great distance, these ENA emissions resemble a thick layer or a wall. The emissions are enhanced in the direction opposite to the convective electric field (E c ). This enhancement reflects the asymmetric shape of the induced magnetic boundary that is close to the planet hemisphere where the E c points toward the Sun-Mars line (-E c hemisphere). The ENA flux shows a positive correlation with the solar wind dynamic pressure. The asymmetry in the ENA emissions is modest during quiet solar wind conditions but becomes more pronounced when the solar wind dynamic pressure increases.

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Exospheres and Energetic Neutral Atoms of Mars, Venus and Titan

Cited by 27 publications

References 236 publications

Influence of Martian crustal magnetic anomalies on the emission of energetic neutral hydrogen atoms

Influence of Martian crustal magnetic anomalies on the emission of energetic neutral hydrogen atoms

Modeling of Venus, Mars, and Titan

Directionality and variability of energetic neutral hydrogen fluxes observed by Mars Express

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