NEAR-MARS SPACE

The space environment of Mars is largely determined by its lack of a substantial planetary magnetic field. In contrast to Earth, Mars does not have radiation belts or an auroral "oval," and its perturbation of the interplanetary medium or solar wind is confined to a relatively small volume. Moreover, the direct interaction of the solar wind plasma with the Martian atmosphere produces a distinctive local energetic particle population of planetary origin, which provides evidence of the possibly significant scavenging of certain elements from Mars over the life of the solar system. In this paper we describe the general characteristics of near-Mars space, as it is known today, including both the ambient interplanetary environment and the ionosphere, upper atmosphere, and regions above that are affected by the presence of Mars.