  Aims. We study the soft X-ray emission induced by charge exchange (CX)
collisions between solar-wind, highly charged ions and neutral atoms of the
Martian exosphere. Methods. A 3D multi species hybrid simulation model with
improved spatial resolution (130 km) is used to describe the interaction
between the solar wind and the Martian neutrals. We calculated velocity and
density distributions of the solar wind plasma in the Martian environment with
realistic planetary ions description, using spherically symmetric exospheric H
and O profiles. Following that, a 3D test-particle model was developed to
compute the X-ray emission produced by CX collisions between neutrals and solar
wind minor ions. The model results are compared to XMM-Newton observations of
Mars. Results. We calculate projected X-ray emission maps for the XMM-Newton
observing conditions and demonstrate how the X-ray emission reflects the
Martian electromagnetic structure in accordance with the observed X-ray images.
Our maps confirm that X-ray images are a powerful tool for the study of solar
wind - planetary interfaces. However, the simulation results reveal several
quantitative discrepancies compared to the observations. Typical solar wind and
neutral coronae conditions corresponding to the 2003 observation period of Mars
cannot reproduce the high luminosity or the corresponding very extended halo
observed with XMM-Newton. Potential explanations of these discrepancies are
discussed.

Earth and Planetary Astrophysics