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Opportunities for magnetospheric research with coordinated cluster and ground-based observations
ESA’s first multi-satellite mission Cluster is unique in its concept of 4 satellites orbiting in controlled formations. This will give an unprecedented opportunity to study structure and dynamics of the magnetosphere. In this paper we discuss ways in which ground-based remote-sensing observations of the ionosphere can be used to support the multipoint in-situ satellite measurements. There are a very large number of potentially useful configurations between the satellites and any one ground-based observatory; however, the number of ideal occurrences for any one configuration is low. Many of the ground-based instruments cannot operate continuously and Cluster will take data only for a part of each orbit, depending on how much high-resolution (‘burst-mode’) data are acquired. In addition, there are a great many instrument modes and the formation, size and shape of the cluster of the four satellites to consider.
These circumstances create a clear and pressing need for careful planning to ensure that the scientific return from Cluster is maximised by additional coordinated ground-based observations. For this reason, ESA established a working group to coordinate the observations on the ground with Cluster. We will give a number of examples how the combined spacecraft and ground-based observations can address outstanding questions in magnetospheric physics. An online computer tool has been prepared to allow for the planning of conjunctions and advantageous constellations between the Cluster spacecraft and individual or combined ground-based systems. During the mission a ground-based database containing index and summary data will help to identify interesting datasets and allow to select intervals for coordinated studies. We illustrate the philosophy of our approach, using a few important examples of the many possible configurations between the satellite and the ground-based instruments
Mars Express Observations of Cold Plasma Structures in the Martian Magnetotail
We present observations from five Mars Express (MEX) orbits in September 2016 while the spacecraft passed through the Martian induced magnetotail at altitudes up to 3,500 km. On these orbits, the Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) instrument was operated in Active Ionospheric Sounding (AIS) mode at much higher altitude than normal, acting as a local sounder and detecting cold plasma structures in this region. In this paper we combine MARSIS tail measurements with solar wind data from the Solar Wind Ion Analyzer (SWIA) instrument and the Magnetometer (MAG) from Mars Atmosphere and Volatile EvolutioN (MAVEN) in order to investigate possible factors affecting plasma transport from the dayside and through the terminator. MARSIS observed structured cold ionospheric plasma along its trajectory, at all altitudes and solar zenith angles (SZAs). Isolated regions of cold plasma were also observed on each orbit as the spacecraft crossed the terminator, even at high altitudes. We conclude that the variability of plasma seen in the tail results from a multifactorial transport process, the development of which cannot be attributed to a sole parameter influencing it, despite the availability of simultaneous high quality solar wind measurements
Understanding space weather to shield society: A global road map for 2015–2025 commissioned by COSPAR and ILWS
status: publishe