Search Publications
The Cluster Magnetic Field Investigation: overview of in-flight performance and initial results
Balogh, A.; Glassmeier, K. -H.; Dunlop, M. W. +10 more
The accurate measurement of the magnetic field along the orbits of the four Cluster spacecraft is a primary objective of the mission. The magnetic field is a key constituent of the plasma in and around the magnetosphere, and it plays an active role in all physical processes that define the structure and dynamics of magnetospheric phenomena on all …
First multispacecraft ion measurements in and near the Earth's magnetosphere with the identical Cluster ion spectrometry (CIS) experiment
Lundin, R.; Escoubet, C. P.; Balsiger, H. +75 more
On board the four Cluster spacecraft, the Cluster Ion Spectrometry (CIS) experiment measures the full, three-dimensional ion distribution of the major magnetospheric ions (H+, He+, He++, and O+) from the thermal energies to about 40 keV/e. The experiment consists of two different instruments: a COmpositi…
Introduction: The Cluster mission
Escoubet, C. P.; Goldstein, M.; Fehringer, M.
The Cluster mission, ESA’s first cornerstone project, together with the SOHO mission, dating back to the first proposals in 1982, was finally launched in the summer of 2000. On 16 July and 9 August, respectively, two Russian Soyuz rockets blasted off from the Russian cosmodrome in Baikonour to deliver two Cluster spacecraft, each into their proper…
First results of electric field and density observations by Cluster EFW based on initial months of operation
Wahlund, J. -E.; André, M.; Khotyaintsev, Y. +22 more
Highlights are presented from studies of the electric field data from various regions along the Cluster orbit. They all point towards a very high coherence for phenomena recorded on four spacecraft that are separated by a few hundred kilometers for structures over the whole range of apparent frequencies from 1 mHz to 9 kHz. This presents completel…
First results from the RAPID imaging energetic particle spectrometer on board Cluster
Livi, S.; Grande, M.; Carter, M. +28 more
The advanced energetic particle spectrometer RAPID on board Cluster can provide a complete description of the relevant particle parameters velocity, V , and atomic mass, A, over an energy range from 30 keV up to 1.5 MeV. We present the first measurements taken by RAPID during the commissioning and the early operating phases. The orbit on 14 Januar…
Early results from the Whisper instrument on Cluster: an overview
André, M.; Krasnoselskikh, V.; Fergeau, P. +22 more
The Whisper instrument yields two data sets: (i) the electron density determined via the relaxation sounder, and (ii) the spectrum of natural plasma emissions in the frequency band 2-80 kHz. Both data sets allow for the three-dimensional exploration of the magnetosphere by the Cluster mission. The total electron density can be derived unambiguousl…
Temporal evolution of the electric field accelerating electrons away from the auroral ionosphere
Balogh, A.; André, M.; Buchert, S. +10 more
The bright night-time aurorae that are visible to the unaided eye are caused by electrons accelerated towards Earth by an upward-pointing electric field. On adjacent geomagnetic field lines the reverse process occurs: a downward-pointing electric field accelerates electrons away from Earth. Such magnetic-field-aligned electric fields in the collis…
Cluster as a wave telescope - first results from the fluxgate magnetometer
Balogh, A.; Glassmeier, K. -H.; Buchert, S. +9 more
The four Cluster spacecraft provide an excellent opportunity to study spatial structures in the magnetosphere and adjacent regions. Propagating waves are amongst the interesting structures and for the first time, Cluster will allow one to measure the wave vector of low-frequency fluctuations in a space plasma. Based on a generalized minimum varian…
Four-point high time resolution information on electron densities by the electric field experiments (EFW) on Cluster
Vaivads, A.; Gustafsson, G.; Décréau, P. +7 more
For accurate measurements of electric fields, spherical double probes are electronically controlled to be at a positive potential of approximately 1 V relative to the ambient magnetospheric plasma. The spacecraft will acquire a potential which balances the photoelectrons escaping to the plasma and the electron flux collected from the plasma. The p…
Active spacecraft potential control for Cluster implementation and first results
Escoubet, C. P.; André, M.; Goldstein, R. +16 more
Electrostatic charging of a spacecraft modifies the distribution of electrons and ions before the particles enter the sensors mounted on the spacecraft body. The floating potential of magnetospheric satellites in sunlight very often reaches several tens of volts, making measurements of the cold (several eV) component of the ambient ions impossible…