Recent Cluster Results on Cusp and Magnetopause Boundary Phenomena
Résumé
The combined data sets of Cluster and Double Star have provided extensive, multi-scale coverage of the Earth's magnetosphere. Since 2001 the Cluster orbit has preferentially sampled the high and mid altitude cusp regions during the spring seasons, and crossed both the high and low latitude, dayside magnetopause at other times. We present an overview of the most recent Cluster research on both the dayside and boundary layer phenomena based predominantly on multipoint studies. The Doublestar TC-1 spacecraft has also sampled either the subsolar region of the magnetopause, or southerly latitudes, at similar local times to cluster. We therefore also review coordinated CLUSTER-Double Star conjunctions for a number of dayside passes to investigate reconnection associated signatures observed at different locations. We Focus on both transient FTEs, arising from opened flux ropes during intermittant reconnection, and comparative boundary layer signatures during cusp and magnetopause transitions and investigate structure and dynamics of the magnetopause and FTE occurance on motion. Cluster provides good coordination with ionospheric instrumentation, particularly the EISCAT and SuperDARN radars and ground magnetomters and we also review investigations of the ground signatures of reconnection (FTEs and boundary layers) and other features of magnetospheric response. The spacecraft are conjugate simulataneously with both the ESR radar on Svalbard, and the Antarctic station at Zhongshan, when the ground stations lie under the cusp position, Cluster is passing out from the northern cusp and TC-1 is near the magnetopause.