Upper Ionosphere of Mars During Solar Quiet and Disturbed Conditions - Planetary Exploration and Science: Recent Results and Advances - page 125

the distribution of proton fluxes with time as observed by GOES 11 at three energies
10, 50 and 100 MeV thus indicating that CMEs erupted from the active regions
on the sun for several hours after each flare. The flare of 17 January was very strong,
and protons of all three energies were accelerated from the heliosphere of the sun
(Fig. 7.7d ). The X-ray and proton fluxes for the flares of 29 May and 31 May
2003 were not as large as those for the flares of 17 January and 13 May 2005.
Figure 7.7a-c represent time series of the measured and calculated total electron
content (TEC) of E region ionosphere for each respective day between 29 May and
3 June 2003, 15 and 20 January 2005 and 12 and 18 May 2005, respectively. MGS
observed the electron density profiles a few hours before and immediately after these
solar flares. Before flaring, the ionosphere of Mars was calm. Soon after the solar
flares, an increase by a factor of 4-5 in the TEC was estimated. The effect of these
flares endured each day for about 1-2 h in the E region ionosphere of Mars. During
the quiet period the value of predicted TEC is higher by a factor of 1.5-2 than the
observed value. This is due to the fact that electron-ambient-electron collisions were
neglected in this model. This process will reduce the modelled TEC.

7.3.2 Effect of CMEs on the Upper Ionosphere

Studying and understanding the effect of CME is a key area of research in planetary
aeronomy. Haider et al. ( 2012 ) were the first to detect the effect of CMEs in the
E region ionosphere of Mars. They examined MGS data between 30 and 31 May
2003, 2 and 3 June 2003 and 16 and 17 May 2005 following the flares of 29 May,
31 May 2003 and 13 May 2005, respectively (see Fig. 7.8a-c ). They found that the
physical processes of magnetic storms (the after effects of CMEs) are different on
Earth and Mars. During a magnetic storm, shock waves driven by CME compress
the Earth's magnetosphere leading to increased energetic particle precipitation into
the ionosphere. This leads to sudden increase in the electron density. The magnetic
storm effects on Mars, on the other hand, have quiet different characteristics. Mars
has no dipolar magnetic field. Therefore, solar wind interacts directly with the
Martian ionosphere, which acts as an obstacle and diverts the solar wind around

Fig. 7.7 ( a ) Solar X-ray flux measured by GOES 12 ( black line ) and calculated by model ( red line )
between 29 May and 3 June 2003 ( b ) Proton flux distributions between 29 May and 3 June 2003
measured by GOES 11 at three energies:

10 MeV ( red colour ), 50 MeV ( black colour )and

100 MeV ( blue colour ). ( c ) Solar X-ray flux measured by GOES 12 ( black line ) and calculated
by model ( red line ) between 15 and 20 January 2005. ( d ) Proton flux distribution between 15 and
20 January 2005 measured by GOES 11 at three energies: 50 MeV

( black colour )and100 MeV ( blue colour ). ( e ) Solar X-ray flux measured by GOES 12 ( black
line ) and calculated by model ( red line ) between 12 and 18 May 2005. ( f ) Proton flux distribution
between 12 and 18 May 2005 measured by GOES 11 at three energies: 10 MeV ( red colour ),
50 MeV ( black colour )and100 MeV ( blue colour ) (Reprinted from Haider et al. ( 2012 ) with
kind permission from Springer)

10 MeV ( red colour ),