Top – simulated proton density (solid) and velocity (dashed) calculated with the CORHEL model for the Mars orbit for the2003/11/18 CME propagating through interplanetary space. According to the simulations the perturbed CME plasma arrived at Mars about a day and a half after the XMM-Newton exposure (represented by the vertical lines). Bottom – same as top only calculated for the Earth orbit. ACE 1-day gliding averages of density and velocity measurements are also plotted in gray for comparison.