Possible effects of the Martian crustal magnetization on its magnetosphere

Szegö, K.

doi:10.1029/1999gl010746

Cited by 10 publications

(3 citation statements)

References 10 publications

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“…Because of the lack of a strong intrinsic global magnetic field, the interaction of Mars with the solar wind on a planetary scale, resembling that of Venus, is essentially an ionospheric/atmospheric one [ Riedler et al , 1989; Cloutier et al , 1999]. This picture remains valid in average even after considering the presence of the linearized crustal remanent magnetic field, which has been recently discovered by Mars Global Surveyor [ Acuña et al , 1998; Connerney et al , 1999] and has been proven to be able to influence locally the geometry of the ionosphere [ Szegö , 2000] and magnetosphere magnetic field [ Ma et al , 2002].…”

Section: Introductionmentioning

confidence: 99%

Martian hydrogen exosphere charge exchange with solar wind

Chen

Cloutier

2003

J. Geophys. Res.

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[1] Charge exchange of solar wind with the Martian exosphere has been shown to play a crucial role in the formation of the magnetic pileup boundary observed by Mars Global Surveyor. However, the question of how the Martian exospheric structure is quantitatively altered by charge exchange of the solar wind remains open. To answer this question, a three-dimensional Monte Carlo exosphere model was developed. In this model the effects of planetary rotation, photoionization, Lyman a scattering, and charge exchange with the solar wind are included. Although the change of exospheric density profile is indistinctive, simulation results show that the existence of the hot atomic hydrogen population produced by charge exchange alters the exospheric temperature structure greatly and the symmetry of the exospheric structure is totally destroyed at high altitude. Another noticeable phenomenon is that charge exchange and Lyman a scattering combine to make the nightside exosphere be cooler than and expand more slowly than the ambient exosphere. In the end we use our simulation results to estimate the contribution of the hot component to Ly a emission. Furthermore, output of our model can be used to predict particle observations made by future missions to Mars.

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Section: Introductionmentioning

confidence: 99%

Martian hydrogen exosphere charge exchange with solar wind

Chen

Cloutier

2003

J. Geophys. Res.

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“…Data from the magnetometer (MAG) and electron reflectometer (ER) experiments on board the Mars Global Surveyor (MGS) have already proven that Mars has no significant global magnetic field but does have some crustal magnetic field [Acura et at., 1998; Ctoutier et at., 1999; Connerhey et at., 1999]. Although the existence of the latter may have some local effects [Szeg6, 2000], the ionosphere is the main obstacle to the solar wind, leading us to the conclusion that the interaction between the solar wind and Mars is like that of other nonmagnetic objects, especially Venus [Ctoutier et at., 1999].…”

Section: Introductionmentioning

confidence: 99%

On the role of charge exchange in the formation of the Martian magnetic pileup boundary

Chen¹,

Cloutier²,

Crider³

et al. 2001

J. Geophys. Res.

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In the magnetic pileup boundary (MPB) of Mars a steep increase in the magnitude of the magnetic field is observed in the data from the magnetometer on board Mars Global Surveyor, and the growth of the field is more precipitous than common solar wind‐ionosphere models predict. Analysis of both Venus and Mars magnetic field data has strongly implied that plasma pressure is exchanged for magnetic pressure in the magnetic pileup field. To explain this, effects of the Martian exosphere must be included. Then charge exchange between the shock‐compressed solar wind protons, which dominate the thermal pressure, and neutral exospheric atoms (mainly H and O) should play a crucial role in the formation of the MPB, as is also inherently required by the conservation of momentum flux. To test this idea, a model of the solar wind interaction with the Martian upper atmosphere, with charge exchange included, is constructed to reproduce the observed magnetic field of the MPB of Mars. The simulation results show that charge exchange is able to account for the sudden buildup of the magnetic field in the Martian MPB, with the implication that the same mechanism produces the magnetic field increase at Venus and comets.

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“… Ness et al [2000] cross correlated the crustal field observations with previous Mars plasma measurements, finding great consistency between the data sets and confirming that these fields are responsible for many of the unusual features of Mars' ionosphere. Phobos 2 data have also been reanalyzed in light of the MGS field measurements, finding anomalous plasma signatures that are probably the result of crustal fields [ Szego , 2000].…”

Section: Introductionmentioning

confidence: 99%

Comparisons of electron fluxes measured in the crustal fields at Mars by the MGS magnetometer/electron reflectometer instrument with a B field–dependent transport code

et al. 2003

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[1] We compare Mars Global Surveyor (MGS) magnetometer/electron reflectometer data with results from a B field-dependent kinetic transport code for ''superthermal'' electrons. The photoelectrons created on crustal field loops, when they are on the dayside, allow for the exploration of the magnetic topology and the upper atmospheric density structure. A case study of a typical orbit of the MGS satellite through the strong crustal field region in the southern hemisphere of Mars is examined. The results indicate that the low solar wind dynamic pressure during the selected orbit allowed for the expansion of the crustal field line to relatively high altitudes. Another feature of the photoelectrons in the crustal field region is that the distribution at high energies (E > 100 eV) is far more isotropic than what is expected from collisional scattering processes alone. Several candidate processes are discussed that might be preferentially scattering high-energy electrons. A final conclusion is that a two-stream model is inadequate for effectively examining photoelectron pitch angle distributions at Mars in the presence of the crustal fields.

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Possible effects of the Martian crustal magnetization on its magnetosphere

Abstract: Abstract.The

Cited by 10 publications

References 10 publications

Martian hydrogen exosphere charge exchange with solar wind

Martian hydrogen exosphere charge exchange with solar wind

On the role of charge exchange in the formation of the Martian magnetic pileup boundary

Comparisons of electron fluxes measured in the crustal fields at Mars by the MGS magnetometer/electron reflectometer instrument with a B field–dependent transport code

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