The arrival of CME's at Earth and other planets leads to a number of different processes of solar wind magnetosphere / exosphere coupling which may vary, depending on the velocity of the CME and the density and steepness of the associated shock-fronts. Also the polarity of the magnetic field structure enclosing the solar ejecta is of crucial importance at magnetised planets. A sudden  compression of the magnetopause (and magnetosphere) leads to associated magnetic effects (like sudden storm commencements) and reconnection at either sub-solar or polar magnetic boundaries (depending of the polarity of the CME magnetic field leads to fundamental changes in the efficiency of energy coupling, transport and conversion within the magnetosphere itself. This in turn results in dramatic changes in the magnetospheric current systems and acceleration of increased fluxes of magnetospheric particles to very high energies, which on Earth can be potentially harmful to man and man-made equipment both on ground and in space. 
At Earth and other magnetised planets with atmospheres also the loss-rate of atmospheric constituents is affected during such events. During extreme CME events some satellites of the outer planets can even find themselves in the unshielded solar wind or magneto-sheath (as e.g. Cassini has observed for Titan).
Unmagnetised planets will experience extreme draping of magnetic fields around the exosphere with deep intrusions of solar wind magnetic fields into the upper atmosphere, with consequent drastic increases of atmospheric loss processes. Even comets have been seen to loose their entire plasma tail during CME encounters. SEP from the original solar flares and from CME shockfronts can penetrate to the surface of the planets and, in particular on Mars, pose potential threats to future astronauts and settlers.
The envelope of variability of planetary objects in our solar system (magnetized and unmagnetised with either thick, thin or no atmosphere, and even magnetospheres in other magnetospheres) allows us to draw conclusions on possible conditions in other similar solar systems where alien planetary environments might be exposed to more or less active stars
For this session we invite papers on subjects illuminating any of the described processes of CME planetary interaction, in particular those of relevance for space weather effects on Earth and  future human exploration of the solar system.