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In-Depth Information
Chapter 7
Upper Ionosphere of Mars During Solar Quiet
and Disturbed Conditions
S.A. Haider
Abstract
In this chapter, we have described upper and lower ionospheric
measurements, which have been obtained from radio occultation experiment
onboard Mariners 6, 7 and 9; Mars 4 and 5; Viking 1 and 2; Mars Global Surveyor;
and Mars Express. The ionisation sources like solar EUV, X-ray and particle
radiations have been discussed. Observations on the upper ionosphere of Mars
during disturbances like aurorae, solar flares, solar energetic particles and coronal
mass ejections are also described. The understanding of complex behaviour of
Martian ionosphere requires a balanced effort in the area of theoretical modelling.
Therefore, we have also reported modelling of the upper ionosphere of Mars during
quiet and disturbed conditions. At present measurements on the ionosphere of Mars
are limited to middle- and high-latitude region. The low-latitude ionosphere of Mars
is not observed. The physics of the low-latitude ionosphere could be very different
from middle- and high-latitude ionosphere. Therefore, it is necessary to look for
opportunities for obtaining observations at low-latitude region.
Keywords
Ionosphere of Mars
7.1
Introduction
The upper ionosphere of Mars has been explored mostly with the radio occultation
experiment onboard Mariner 6, 7 and 9 (Fjeldbo et al.
1970
; Kliore et al.
1973
);
Mars 2, 3, 4, 6 and 7 (Kolosov et al.
1975
; Vasiliev et al.
1975
;Savichand
Samovol
1976
); Viking 1 and 2 (Fjeldbo et al.
1977
); and more recently by
Mars Global Surveyor (MGS) (Hinson et al.
1999
; Tyler et al.
2001
)andMars
Express (MEX) (Pätzold et al.
2005
). In addition to radio occultation experiment,
MEX also carried Mars Advanced Radar for Subsurface and Ionosphere Sounding
(MARSIS) experiment, which provided electron density profiles well above the
main ionospheric peak (Gurnett et al.
2005
). The daytime ionosphere models, which
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