Empirical Model of the Martian Dayside Ionosphere: Effects of Crustal Magnetic Fields and Ionizing Flux at Higher Altitudes

Abstract:

We use electron density profiles measured by the MARSIS instrument on board
the Mars Express spacecraft to investigate the effects of possible controlling
parameters unconsidered in the empirical model of Nemec et al. (2011).
Specifically, we focus on the effects of crustal magnetic fields and F10.7
proxy of the ionizing flux at higher altitudes. It is shown that while the peak
density and altitude are nearly unaffected by crustal magnetic fields, electron
densities at higher altitudes are significantly increased in areas of stronger
magnetic fields. Moreover, while the empirical model accounted for the variable
ionizing flux at low altitudes, the high altitude diffusive region was
parameterized only by the solar zenith angle and the altitude. It is shown that
this can lead to considerable inaccuracies. A simple correction of the previous
model, which takes into account both these effects, is suggested.