Variability of the altitude of the Martian sheath

Brain, David; Halekas, J. S.; Lillis, Robert J.; Mitchell, David; Lin, R. P.; Crider, D. H.

doi:10.1029/2005gl023126

Cited by 129 publications

(184 citation statements)

References 19 publications

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“…The existence of an asymmetry is suggested by Vennerstrom et al (2003) who conducted a statistical analysis of the magnetic field data collected by MGS. The same phenomenon is discussed by Brain et al (2005Brain et al ( , 2006. However, a detailed global data analysis concerning the formation of the ICB has not yet been performed.…”

Section: The Martian Plasma Environment (Mmentioning

confidence: 84%

Physics of the Ion Composition Boundary: a comparative 3-D hybrid simulation study of Mars and Titan

et al. 2007

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Abstract. The plasma environments of Mars and Titan have been studied by means of a 3-D hybrid simulation code, treating the electrons as a massless, charge-neutralizing fluid, whereas ion dynamics are covered by a kinetic approach. As neither Mars nor Titan possesses a significant intrinsic magnetic field, the upstream plasma flow interacts directly with the planetary ionosphere. The characteristic features of the interaction region are determined as a function of the alfvénic, sonic and magnetosonic Mach number of the impinging plasma. For the Martian interaction with the solar wind as well as for the case of Titan being located outside Saturn's magnetosphere in times of high solar wind dynamic pressure, all three Mach numbers are larger than 1. In such a scenario, the interaction gives rise to a so-called Ion Composition Boundary, separating the ionospheric plasma from the ambient flow and being highly asymmetric with respect to the direction of the convective electric field. The formation of these features is explained by analyzing the Lorentz forces acting on ionospheric and ambient plasma particles. Titan's plasma environment is highly variable and allows various different combinations of the three Mach numbers. Therefore, the Ion Composition Boundary may vanish under certain circumstances. The relevant physical mechanism is illustrated as a function of the Mach numbers in the upstream plasma flow.

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Section: The Martian Plasma Environment (Mmentioning

confidence: 84%

Physics of the Ion Composition Boundary: a comparative 3-D hybrid simulation study of Mars and Titan

et al. 2007

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“…Since there is no magnetometer on MEX, the vector of the spacecraft position relative to the vectors B IMF and E could be determined only as a proxy from the MGS measurements on the mapping orbits at h ∼ 400 km in some reference point in the northern hemisphere and then adjusted to the MEX observations (Brain et al, 2006;. Although this method is rather crude since the orbital period of MGS is about 2 hours and the IMF orientation often significantly varies during such time we try to use it plotting the inbound and outbound orbital legs for 12 orbits sampling the same solar zenith angles as a function of the Z IMF (Fig.…”

Section: Discussionmentioning

confidence: 99%

Upper ionosphere of Mars is not axially symmetrical

et al. 2012

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The measurements carried out by the ASPERA-3 and MARSIS experiments on board the Mars Express (MEX) spacecraft show that the upper Martian ionosphere (h ≥ 400 km) is strongly azimuthally asymmetrical. There are several factors, e.g., the crustal magnetization on Mars and the orientation of the interplanetary magnetic field (IMF) which can give rise to formation of ionospheric swells and valleys. It is shown that expansion of the ionospheric plasma along the magnetic field lines of crustal origin can produce bulges in the plasma density. The absense of a magnetometer on MEX makes the retrieval of an asymmetry caused by the IMF more difficult. However hybrid simulations give a hint that the ionosphere in the hemisphere (E − ) to which the motional electric field is pointed occurs more inflated than the ionosphere in the opposite (E + ) hemisphere.

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“…4534 N. J. T. Edberg et al: Rosetta and Mars Express fields Edberg et al, 2008;Dubinin et al, 2008b) and the solar wind dynamic pressure (Crider et al, 2003;Brain et al, 2005;Dubinin et al, 2006). They have all been shown to be important for determining the location of the boundaries in statistical studies.…”

Section: Introductionmentioning

confidence: 99%

“…The magnetosheath stretches down to the magnetic pileup boundary (MPB) where interplanetary magnetic field (IMF) piles up and drapes around the planet. Factors controlling the location of the BS and MPB include the IMF direction (Zhang et al, 1991;Vignes et al, 2002;Brain et al, 2005;Dubinin et al, 2008a), crustal…”

Section: Introductionmentioning

confidence: 99%

Rosetta and Mars Express observations of the influence of high solar wind pressure on the Martian plasma environment

et al. 2009

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Abstract. We report on new simultaneous in-situ observations at Mars from Rosetta and Mars Express (MEX) on how the Martian plasma environment is affected by high pressure solar wind. A significant sharp increase in solar wind density, magnetic field strength and turbulence followed by a gradual increase in solar wind velocity is observed during ∼24 h in the combined data set from both spacecraft after Rosetta's closest approach to Mars on 25 February 2007. The bow shock and magnetic pileup boundary are coincidently observed by MEX to become asymmetric in their shapes. The fortunate orbit of MEX at this time allows a study of the inbound boundary crossings on one side of the planet and the outbound crossings on almost the opposite side, both very close to the terminator plane. The solar wind and interplanetary magnetic field (IMF) downstream of Mars are monitored through simultaneous measurements provided by Rosetta. Possible explanations for the asymmetries are discussed, such as crustal magnetic fields and IMF direction. In the same interval, during the high solar wind pressure pulse, MEX observations show an increased amount of escaping planetary ions from the polar region of Mars. We link the high pressure solar wind with the observed simultaneous ionCorrespondence to: N. J. T. Edberg (ne@irfu.se) outflow and discuss how the pressure pulse could also be associated with the observed boundary shape asymmetry.

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Variability of the altitude of the Martian sheath

Cited by 129 publications

References 19 publications

Physics of the Ion Composition Boundary: a comparative 3-D hybrid simulation study of Mars and Titan

Physics of the Ion Composition Boundary: a comparative 3-D hybrid simulation study of Mars and Titan

Upper ionosphere of Mars is not axially symmetrical

Rosetta and Mars Express observations of the influence of high solar wind pressure on the Martian plasma environment

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