The solar wind, which is material ejected by the Sun, interacts directly with the upper atmosphere of Mars and its plasma environment. This interaction region is enclosed by a bow shock, a boundary where the solar wind is rapidly slowed so it can be diverted around the Martian space environment. The Sun's solar activity, the behavior of its material and light output over time, varies over many different periods, resulting in a very dynamic Martian space environment. Studies of how the solar cycle, a ~11 year variation in the solar activity, impacts the Martian space environment has been inhibited by a lack of continuous observations of the environment. However, the European Space Agency's Mars Express (MEX) mission has surveyed the Martian environment for >11 years.

The data published here includes the outputs of a study exploiting the longevity of this mission to investigate how the Martian bow shock varies over this long period for the first time (Hall et al., 2019). In contrast to previous time-limited studies, we show that the Martian bow shock position is impacted by the solar activity, moving away from Mars as the solar activity increases. These results are important to future studies and missions that probe the interaction of the Martian atmosphere with the solar wind.

These files list bow shock crossings identified from the MEX mission has been created based on the ASPERA-ELS instrument observations. If this dataset is used, please cite the following two papers:

Hall, B., M. Lester, B. Sanchez-Cano, J. D. Nichols, D. J. Andrews, N. J. T. Edberg, H. J. Opgenoorth, M. Franz, M. Holmstrom, R. Ramstad, O. Witasse, M. Cartacci, A. Cicchetti, R. Noschese, and R. Orosei (2016), Annual variations in the Martian bow shock location as observed by the Mars Express mission, J. Geophys. Res. Sp. Phys., 121 (11), 11,474-11,494, doi:10.1002/2016JA023316.

Hall, B., B. Sánchez-Cano, J. A. Wild, M. Lester, and M. Holmstrom (2019), The Martian bow shock over solar cycle 23-24 as observed by the Mars Express mission, J. Geophys. Res. Sp. Phys. (DOI etc to be added upon publication of the paper)