On the elastic and inelastic collisions between precipitating energetic hydrogen atoms and Martian atmospheric neutrals

Kallio, Esa; Barabash, S.

doi:10.1029/2000ja900077

Cited by 23 publications

(21 citation statements)

References 20 publications

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“…This means that in their model, the protons are not artificially cut away from the whole simulation, but are treated as particles colliding with atmospheric neutrals. These collisions backscatter the ions (Kallio and Barabash, 2001). The ions may hit the inner boundary a few times more, instead of being immediately removed after one hit on the inner boundary.…”

Section: Discussionmentioning

confidence: 99%

“…It means that the height of the depletion layer (height from which the ions have no room to gyrate because they are taken away) depends on the particle energy and on the magnetic field. In reality, the ions are not immediately lost, but scattered back by the atmosphere after ion-neutral collisions (see Kallio and Barabash, 2001, their figure 2).…”

Section: Ion Precipitationmentioning

confidence: 99%

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Hybrid simulations of proton precipitation patterns onto the upper atmosphere of Mars

et al. 2012

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We study the dependence of proton precipitation patterns onto the Martian upper atmosphere on altitude, proton energy, proton origin, and in a lesser extent, solar zenith angle, using the HYB-Mars model, a 3D quasineutral hybrid model. We find that the flux of precipitating protons has a strong altitude dependence: on the dayside, the flux of precipitating protons decreases substantially when the altitude over Mars decreases. We also find that the contribution of exospheric protons to the deposition is significant and its spatial distribution is not identical to that of the solar wind protons. In addition, the low energy proton population comes mainly from the newborn planetary protons. The energized pick-up protons and solar wind protons contribute to the higher energy proton population. The study also confirms that the proton precipitation is highly asymmetric with respect to the direction of the convection electric field in the solar wind. The study implies that the Martian induced magnetosphere protects the upper atmosphere effectively against proton precipitation.

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Section: Discussionmentioning

confidence: 99%

Section: Ion Precipitationmentioning

confidence: 99%

Hybrid simulations of proton precipitation patterns onto the upper atmosphere of Mars

et al. 2012

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“…After interaction (elastic and inelastic collisions) with Mars' atmosphere a fraction of the precipitated ENAs will be emitted again (backscattered), with a different velocity. Kallio and Barabash [2000] have investigated the local properties of this process by Monte Carlo simulations and by solving a transport equation. A global three‐dimensional investigation by Monte Carlo simulations is presented by Kallio and Barabash [2001].…”

Section: Ena Imagesmentioning

confidence: 99%

Energetic neutral atoms at Mars 1. Imaging of solar wind protons

2002

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[1] Energetic neutral atom (ENA) images are computed from an empirical solar wind proton model and recent models of the Martian exosphere. The proton model describes the proton bulk velocity in the interaction region and the neutral model the profiles of H, H 2 and O (hot) and O (thermal). We assume a Maxwellian proton velocity distribution. The ENA production model is analytical; thus an ENA image can be constructed for any vantage point by line of sight integration, and we present examples of such images. In this work we study the influence of different parameters in the input models on the generated images and examine the relative importance of the different parameters on the global ENA production rate as well as on image morphology for particular vantage points. All together our parameter set includes 14 variables for solar wind conditions, flow geometry, and the exosphere model. Changing the parameters also makes it possible to mimic various features of the solar wind-Mars interaction, such as some of the effects caused by the recently observed magnetic anomalies. It is found that the exobase temperature of atomic hydrogen is the parameter that affects the ENA production and images most. We also investigate the backscattering of ENAs that precipitate on the Martian atmosphere. It is found to be an important effect for views of Mars in the antisunward direction. The outflux of ENAs from the near Mars region is studied, and two maxima are found. One at an angle of approximately 115°to the Mars-Sun line corresponding to ENAs produced downstream of the bow shock and one at approximately 150°corresponding to ENAs produced upstream of the bow shock in the solar wind.

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“…In charge-exchange reactions with neutral atmospheric components-atomic hydrogen and oxygenthermal ions in the planetary ionospheres turn into fast neutral atoms on ballistic trajectories reaching exospheric altitudes (Kallio et al , 1997;Kallio and Barabash, 2000). However, for the Martian atmosphere, a more important source of hot oxygen is the dissociative recombination reaction of the dominant ionospheric ion .…”

Section: Introductionmentioning

confidence: 98%

Stochastic models of hot planetary and satellite coronas: a photochemical source of hot Oxygen in the upper atmosphere of Mars

Krestyanikova¹,

Shematovich

2005

Sol Syst Res

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The processes of the kinetics and transport of hot oxygen atoms in the upper atmosphere of Mars are studied. A reaction of dissociative recombination of the main ionospheric ion with thermal electrons is considered as a photochemical source of suprathermal oxygen atoms. Oxygen atoms are formed in the dissociative recombination reaction with an excess of kinetic energy of about 0.4-4 eV and lose that energy in elastic and inelastic collisions with the ambient thermal atmospheric gas. The altitude distributions of the concentrations of neutral and ionized components, as well as their temperatures, were taken from Krasnopolsky (2002). Unlike the models published earlier, detailed calculations of the formation, collisional kinetics, and transport of suprathermal oxygen atoms in the thermosphere-exosphere transition region of the upper atmosphere of Mars have been made for the first time. For this, we used a stochastic model of the formation of a hot planetary corona (Shematovich, 2004). It has been shown that the considered photochemical source of suprathermal oxygen leads to the formation of the hot corona and to higher nonthermal losses of oxygen from the upper atmosphere of Mars due to escape fluxes. The detailed energy spectra of the fluxes of suprathermal atomic oxygen were calculated for the thermosphere-exosphere transition region of the Martian atmosphere. O 2 +

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On the elastic and inelastic collisions between precipitating energetic hydrogen atoms and Martian atmospheric neutrals

Abstract: Abstract.Properties

Cited by 23 publications

References 20 publications

Hybrid simulations of proton precipitation patterns onto the upper atmosphere of Mars

Hybrid simulations of proton precipitation patterns onto the upper atmosphere of Mars

Energetic neutral atoms at Mars 1. Imaging of solar wind protons

Stochastic models of hot planetary and satellite coronas: a photochemical source of hot Oxygen in the upper atmosphere of Mars

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