Venus‐like interaction of the solar wind with Mars

The Plasma Environment of Mars

“…The MGS magnetometer measurements indeed show that the magnetic field in the ionosphere are largely induced (except in regions with significant crustal anomaly fields) (Acuna et al, 1998;Connerney et al, 1999;Cloutier et al, 1999). This is illustrated in Figure 5.5, which shows the measured magnetic field strength and orientation in the ionosphere.…”

“…This is illustrated in Figure 5.5, which shows the measured magnetic field strength and orientation in the ionosphere. Note that the magnetic field is mainly horizontal with a strength of roughly 50 nT or less (Mitchell et al, 2000), as expected for fields induced by the solar wind interaction (Shingawa and Cravens, 1989;Krymskii, 1992;Cloutier et al, 1999). A boundary layer is evident in the superthermal electron fluxes, as discussed above, yet there is no obvious signature of this layer in the magnetic field.…”

“…One example of such conditions is given in Figure 5.6 for day 234 of 1998. Cloutier et al ( 1999) produced a hodogram for one of the magnetic structures and demonstrated that it was a 'force-free' magnetic flux rope. Magnetic flux ropes with similar helical structures were commonly observed by the PVO magnetometer in 'unmagnetized' ionospheres of Venus Luhmann and Cravens, 1991).…”

“…In fact, most of the current understanding of magnetic field draping comes from investigations of Venus and comets starting with Alfven's (1957) theory and subsequent applications (e.g. Luhmann, 1986;Schwingenschuh et al, 1987;Cloutier et al, 1999;Mazelle et al, 2002). Figure 3.12 is a sketch depicting the magnetic field lines, and the parameters defining the draping geometry.…”

Possible effects of the Martian crustal magnetization on its magnetosphere

“…Most of these anomalous fields appear to be concentrated in the Southern Hemisphere, but there are several crustal sources scattered also at other locations, among other close to the Martian equator between 70 ø through 0 ø to 240 ø West latitude and within 4-10 ø in longitude. MGS also carried an electron reflectometer, the plasma measurements showed that the Martian magnetosphere is very similar to that of Venus in numerous respects [Cloutier et al, 1999]. The Phobos-2 spacecraft was better instrumented than MGS to study in detail the plasma environment of Mars, however, even during its first few elliptical orbits did not get closer to the surface than 850 km.…”