Ionospheric ambipolar electric fields of Mars and Venus: Comparisons between theoretical predictions and direct observations of the electric potential drop.

We test the hypothesis that their dominant driver of a planetary ambipolar electric field is the ionospheric electron pressure gradient (∇ ). The ionospheres of Venus and Mars are mapped using Langmuir probe measurements from NASA's and missions. We then determine the component of the ionospheric potential drop that can be explained by the electron pressure gradient drop along a simple draped field line.

Strong coronal channelling and interplanetary evolution of a solar storm up to Earth and Mars.

The severe geomagnetic effects of solar storms or coronal mass ejections (CMEs) are to a large degree determined by their propagation direction with respect to Earth. There is a lack of understanding of the processes that determine their non-radial propagation. Here we present a synthesis of data from seven different space missions of a fast CME, which originated in an active region near the disk centre and, hence, a significant geomagnetic impact was forecasted.