Multiscale, multipoint measurements from Cluster: Advancing our scientific understanding of geospace

Cluster is the first multispacecraft mission with identical instrumentation designed to resolve spatial and temporal structures in geospace. The orbits of the four Cluster spacecraft are variable and are adjusted periodically to place the spacecraft into configurations that optimize the three-dimensional capabilities of the instrumentation. During the mission, the relative distances between the spacecraft achieved so far have ranged from 100 to 5000 km. In the summer of 2005, the maximum separations were increased to 10,000 km. The primary results of Cluster include: determining the spatial scales of such transient three-dimensional phenomena as the short large amplitude magnetic structures (SLAMS) ahead of the parallel bow shock, the scale of Earth's bow shock, the properties of bursty bulk flows in the plasmasheet, detailed measurements of the diffusion regions characteristic of magnetic reconnection events both in the magnetotail, at the magnetopause, and in the dayside polar cusps, and determinations of the source locations of both continuum radiation and auroral kilometric radiation. Space restrictions only permit a subset of those results to be mentioned.