Articles | Volume 33, issue 10
Ann. Geophys., 33, 1221–1235, 2015

Special issue: Dynamic processes in geospace

Ann. Geophys., 33, 1221–1235, 2015
Review paper
 | Highlight paper
02 Oct 2015
Review paper  | Highlight paper | 02 Oct 2015

Recent highlights from Cluster, the first 3-D magnetospheric mission

C. P. Escoubet1, A. Masson2, H. Laakso1, and M. L. Goldstein3 C. P. Escoubet et al.
  • 1ESA/ESTEC, Noordwijk, the Netherlands
  • 2ESA/ESAC, Madrid, Spain
  • 3NASA/GSFC, Greenbelt, MD, USA

Abstract. The Cluster mission has been operated successfully for 14 years. During this time period, the evolution of the orbit has enabled Cluster to sample many more magnetospheric regions than was initially anticipated. So far, the separation of the Cluster spacecraft has been changed more than 30 times and has ranged from a few kilometres up to 36 000 km. These orbital changes have enabled the science team to address a wide variety of scientific objectives in key regions of Earth's geospace environment: the solar wind and bow shock, the magnetopause, polar cusps, magnetotail, plasmasphere and the auroral acceleration region. Recent results have shed new light on solar wind turbulence. They showed that the magnetosheath can be asymmetric under low Mach number and that it can contain density enhancement that may affect the magnetosphere. The magnetopause was found to be thinner and to have a higher current density on the duskside than on the dawnside. New methods have been used to obtain characteristic of the magnetotail current sheet and high-temporal-resolution measurements of electron pitch angle within flux transfer events (FTEs). Plasmaspheric wind has been discovered, and the refilling of the plasmasphere was observed for the first time over a very wide range of L shells. New models of global electric and magnetic fields of the magnetosphere have been obtained where Cluster, due to its polar orbit, has been essential. Finally, magnetic reconnection was viewed for the first time with high-resolution wave and electron measurements and acceleration of plasma was observed during times of varying rate of magnetic reconnection. The analysis of Cluster data was facilitated by the creation of the Cluster Science Data System (CSDS) and the Cluster Science Archive (CSA). Those systems were implemented to provide, for the first time for a plasma physics mission, a long-term public archive of all calibrated high-resolution data from all instruments.

Short summary
This paper presents recent highlights from the Cluster mission on solar wind turbulence, magnetopause asymmetries and magnetosheath density enhancements, dipolarisation currents, reconnection variability, FTE in greatest detail, plasmaspheric wind and re-filling of the plasmasphere, radiation belts, updates of magnetospheric electric and magnetic field models, and magnetosheath and magnetopause properties under low Mach number. Public access to all high-resolution data (CSA) is also presented.