Magnetic activity at Mars – Mars Surface Magnetic Observatory

We use the extensive database of magnetic observations from the Mars Global Surveyor to investigate magnetic disturbances in the Martian space environment statistically, both close to and far from crustal anomalies. We discuss the results in terms of possible ionospheric and magnetospheric currents, and use this to provide an estimate of the expected magnetic disturbances at the Martian surface. Far from crustal anomaly regions the expected magnetic disturbances originating from currents associated with the induced magnetosphere are very weak at the day-side, but most likely larger on the night-side. Close to crustal anomalies the expected surface perturbation is larger and more variable both in space and time. It is important to note that these variations are not confined to the intense crustal anomalies in the southern hemisphere, but occur in large parts of the equatorial region. The disturbances around medium intensity radial anomalies in the equatorial region appear to derive from local current loops or vortices around cusp-like radial fields, acting to partly cancel the crustal field. The radial perturbation is further found to depend on upstream solar wind dynamic pressure. We define a magnetic experiment at the martian surface, the Mars Surface Magnetic Observatory (MSMO) including the science objectives, science experiment requirements, instrument and basic operations. We find the experiment to be feasible within the constraints of proposed stationary landing platforms. ► Significant magnetic disturbances are observed close to crustal magnetic anomalies at the day-side. ► The disturbances are not confined to the south but occur also in large parts of the equatorial region. ► Close to the medium sized anomalies the data pattern indicates the presence of current loops. ► Far from crustal anomalies ground signals are expected at the night-side and during storm events. ► The Mars Surface Magnetic Observatory, i.e. the MSMO experiment is presented.