Space Weather effects on Mars’ ionosphere: From our current knowledge to the way forward

Planetary Space Weather is an emerging topic of increasing interest. Forecast this planetary space weather, however, is currently very challenging mainly due to the lack of continuous solar wind observations for each planet. In the particular case of Mars, understanding the ionospheric behaviour following Space Weather activity is essential in order to assess the response of the Martian plasma environment to the dissipation of energy from solar storms. Moreover, it gives information on the effects on the current technology deployed on the red planet. Despite the recent considerable exploration, however, there is still no continuous upstream solar wind observations at Mars. This fact makes the analysis of the different Martian plasma datasets challenging, relying on solar wind models and upstream solar wind observations at 1 AU (e.g. at Earth’s L1 point, STEREO, etc.) when Mars and those satellites are in apparent opposition or perfectly aligned in the Parker spiral.

This lecture will focus on our current knowledge of the Martian ionosphere, which is the layer that links the neutral atmosphere with space, and acts as the main obstacle to the solar wind. In particular, I will focus on our recent advances in the understanding of the Martian ionospheric reaction to different Space Weather events during the solar cycle, both from the data analysis and ionospheric modelling perspectives. Some important aspects to consider are the bow shock, magnetic pileup boundary, and ionopause characterization, as well as the behaviour of the topside and bottomside of the ionosphere taking into account the planet’s orbital eccentricity. Moreover, I will show the effect of electron precipitation from large Space Weather events in the very low Martian ionosphere, a region that it is non-accessible to in-situ spacecraft observations. Finally, I will conclude the presentation by giving my perspective on some of the key outstanding questions that remain unknown, and I consider they constitute the next generation of Mars’ ionospheric and Space Weather science and exploration.