Coordinated Coverage of the Ring Current, Cusp and Adjacent FACs with Cluster and Swarm

We explore the capability of Swarm-Cluster coordination for probing the behavior of the ring current (RC), field aligned currents (FAC) and cusp currents at medium and low orbits. The RC and connecting R2 FACs influence the geomagnetic field at low Earth orbit (LEO) and are sampled in situ by the four Cluster spacecraft every perigee pass. Coordination of the configuration of the three Swarm spacecraft with the constellation of the four Cluster spacecraft has been planned through joint operations; providing a set of distributed, multi-point measurements covering this region. A particularly close coordination of all spacecraft has been achieved during the start of the Swarm operations. We show preliminary study of the morphology and influence of the ring current from the in-situ RC and associated FACs determined directly from the 4-spacecraft Cluster perigee observations. We report here preliminary results of joint science targets, including coordinated cusp encounters; the comparative significance of the connecting R2 FACs, and the use and application of new analysis techniques derived from the calculation of curl B and magnetic gradients to compare estimates of the current distributions. For context, we will report on the coordination of Champ and Cluster data to interpret and resolve the R1 and R2 FACs using Champ derived models of the associated auroral boundaries.