The influence of crustal magnetism on the solar wind interaction with Mars: recent observations

Mars is a unique obstacle to the solar wind flow. It lacks a significant global magnetic field but does possess an extensive exosphere/ionosphere which interacts with the incident solar wind in a manner similar to Venus and comets. However, in contrast to Venus and comets, there are very strong, localized regions of magnetization in the crust of Mars. These crustal magnetic fields contribute to the Martian obstacle locally. As Mars rotates under the Sun, the combination creates an asymmetric and time-varying object. The wealth of data from the Mars Global Surveyor mission has enabled great insights into this interaction. We highlight recent results from the Magnetometer/Electron Reflectometer instrument that illuminate aspects of the amount of influence the crustal magnetic fields have on the solar wind interaction with Mars. They include observations of the plasma flow boundaries like the bow shock, the magnetic pileup boundary, and the photoelectron boundary. In addition, we review their influence on features such as magnetic flux ropes, ionospheric scale heights, and magnetic field morphology. (C) 2003 COSPAR. Published by Elsevier Ltd. All rights reserved.