Upper Ionosphere of Mars During Solar Quiet and Disturbed Conditions - Planetary Exploration and Science: Recent Results and Advances - page 135

Fig. 7.15 Schematic view of the downward electron beams and the formation of upward flux of
oxygen ions at the foot points of the Martian crustal magnetic fields. Transverse heating of the O C

ions and other ion species will lead to the generation of ion conics, which are to be converted to
ion beams at higher altitude. Parallel electric fields will be maintained by the V-shaped potential
structure (Reprinted from Ip ( 2012 ) with permission from Elsevier)

7.5 Ionospheric Models

Fox et al. ( 1996 ) carried out a model calculation of the thermosphere and ionosphere
of Mars and calculated neutral densities, temperature, ion production rates and
densities of ions and electrons during solar minimum and maximum conditions.
They found that the electron density increased by a factor of 3 during solar
maximum condition in comparison to that estimated for solar minimum condition.
These model results were found to be in good agreement with the radio occultation
measurements made by Viking 1 and Mariners 6 and 7 during solar minimum and
solar maximum conditions, respectively. Fox et al. ( 1996 )usedEq. 7.1 to calculate
the ion and electron densities in the Martian ionosphere. In this calculation, the
model atmospheres for low and high solar activities were used from the MTGCM
model of Bougher et al. 1990 . Using the photochemical model, Mendillo et al.
( 2004 ) estimated noontime TEC at subsolar latitude of Mars for aphelion and
perihelion positions during solar minimum and solar maximum periods. In this
calculation neutral atmosphere and solar flux were taken from Bougher et al. ( 1990 )
and Tobiska et al. ( 2000 ), respectively, for solar maximum/minimum conditions.
The results of these model calculations are shown in Fig. 7.16 . It can be seen that
TEC increased in the Mars' ionosphere by a factor of 2 during solar maximum