Bow Shock and Upstream Phenomena at Mars

Mazelle, C.; Winterhalter, D.; Sauer, K.; Trotignon, J. G.; Acuña, M. H.; Baumgärtel, K.; Bertucci, C.; Brain, David; Brecht, S. H.; Delva, M.; Dubinin, E.; Øieroset, M.; Slavin, J. A.

doi:10.1023/b:spac.0000032717.98679.d0

Cited by 142 publications

(136 citation statements)

References 140 publications

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“…For a larger data set the statistics will be better which will probably give a clearer result, but when looking at a shorter interval like this, the system is equally, or even more, influenced by other factors. The θ Bn effect has been suggested to be rather limited at Mars due the small obstacle shape compared to the ion-gyroradius as well as due to its extended exosphere as explained by Mazelle et al (2004).…”

Section: Discussionmentioning

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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Section: Discussionmentioning

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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“…In reality, the configuration of the magnetic field and the solar wind will be neither of these extreme cases, so the general case for the ion distribution will be a ring-beam, generating waves observed at the specific ion's cyclotron frequency in the spacecraft frame. The cyclotron waves can theoretically be expected in magnetic field observations at any location where pick-up in adequate quantity from the neutral planetary atmosphere is possible; they propagate nearly parallel to the magnetic field and were reported at Mars (Russell et al 1990b;Brain et al 2002;Mazelle et al 2004;Bertucci et al 2005), at Saturn (Leisner et al 2006), at Jupiter's satellites (e.g. Huddleston et al 1997;Volwerk et al 2001) and in the environment of active comets (e.g.…”

Section: Importance Of Upstream Wavesmentioning

confidence: 99%

“…The opposite signs in expression (3) account for the inversion of the polarization of the wave in the spacecraft frame with respect to the one observed in the solar wind frame; this effect is called "anomalous Doppler-effect" (Mazelle and Neubauer 1993). The local ion cyclotron frequency of the waves as observed in the spacecraft frame is the crucial criterion to identify them as generated by planetary ions and not by species of solar wind origin; furthermore, they are transverse left-hand polarized waves, propagating nearly parallel to the magnetic field (Mazelle et al 2004).…”

Section: Waves At the Ion Cyclotron Frequencymentioning

confidence: 99%

Upstream Ion Cyclotron Waves at Venus and Mars

2011

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The occurrence of waves generated by pick-up of planetary neutrals by the solar wind around unmagnetized planets is an important indicator for the composition and evolution of planetary atmospheres. For Venus and Mars, long-term observations of the upstream magnetic field are now available and proton cyclotron waves have been reported by several spacecraft. Observations of these left-hand polarized waves at the local proton cyclotron frequency in the spacecraft frame are reviewed for their specific properties, generation mechanisms and consequences for the planetary exosphere. Comparison of the reported observations leads to a similar general wave occurrence at both planets, at comparable locations with respect to the planet. However, the waves at Mars are observed more frequently and for long durations of several hours; the cyclotron wave properties are more pronounced, with larger amplitudes, stronger left-hand polarization and higher coherence than at Venus. The geometrical configuration of the interplanetary magnetic field with respect to the solar wind velocity and the relative density of upstream pick-up protons to the background plasma are important parameters for wave generation. At Venus, where the relative exospheric pick-up ion density is low, wave generation was found to mainly take place under stable and quasi-parallel conditions of the magnetic field and the solar wind velocity. This is in agreement with theory, which predicts fast wave growth from the ion/ion beam instability under quasi-parallel conditions already for low relative pick-up ion density. At Mars, where the relative exospheric pick-up ion density is higher, upstream wave generation may also take place under stable conditions when the solar wind velocity and magnetic field are quasi-perpendicular. At both planets, the altitudes where upstream proton cyclotron waves were observed (8 Venus and 11 Mars radii) are comparable in terms of the bow shock nose M. Delva ( )

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“…For the smaller bodies, Mars and Titan, the grid size is often smaller than the ion skin depth and boundary layers of the interaction can be resolved. For example, the thickness of the bow shock and magnetic pile-up boundary at Mars and Venus are on the order of the ion skin depth (Mazelle et al 2004) as is the current sheet thickness at Titan and Mars (Halekas et al 2006;Wahlund et al 2005). However, resolving the ion skin depth violates the assumptions of some models.…”

Section: Assumptions Of Mhd Modelsmentioning

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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Bow Shock and Upstream Phenomena at Mars

Cited by 142 publications

References 140 publications

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

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

Upstream Ion Cyclotron Waves at Venus and Mars

Modeling of Venus, Mars, and Titan

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