Search Publications
Density irregularities in the plasmasphere boundary layer: Cluster observations in the dusk sector
André, M.; Décréau, P. M. E.; Canu, P. +7 more
We present observations of plasma density structures crossed by the CLUSTER spacecraft constellation near orbit perigee, with the spacecraft located in the vicinity of the plasmapause boundary. Although the constellation is not arranged as a perfect tetrahedron, the four-point measurements reveal interesting properties of density structures, unkno…
Multi-point observation of the high-speed flows in the plasma sheet
Balogh, A.; Zhang, T. L.; Klecker, B. +9 more
The structure of the high-speed flows in the midtail plasma sheet is discussed based on results from multi-point observation of Cluster spacecraft in summer 2001 and 2002. The average rate of change in flow speed along the "dawn-dusk" direction (perpendicular to the main flow and in the plane of the tail current sheet) and along the "north-south" …
Neutral sheet normal direction determination
Balogh, A.; Zhang, T. L.; Glassmeier, K. -H. +5 more
One of the important parameters in magnetotail studies is the thickness of the current sheet. The determination of this thickness is subject to many assumptions of the geometry, such as the current sheet normal direction. The minimum variance analysis (MVA) has been widely used in studies of the current sheet in the tail or at the magnetopause wit…
Analysis of Cluster spacecraft potential during active control
Escoubet, C. P.; André, M.; Décréau, P. M. E. +4 more
The floating potential of a spacecraft is determined by an equilibrium between photo-electron emission from the sunlit spacecraft surfaces and the plasma electron current, while other currents play a secondary role. On the Cluster spacecraft, the presence of the experiment ASPOC to control the potential by an ion beam with currents up to several t…
The response of the near earth magnetotail to substorm activity
Khurana, K. K.; McPherron, R. L.; Thompson, S. +3 more
The large scale structure of the current sheet in the terrestrial magnetotail is often represented as the superposition of a constant northward-oriented magnetic field component ( Bz) and a component along the Earth-Sun direction ( Bx) that varies with distance from the center of the sheet ( z0 in GSM) as in a Hams…
Cluster observations of magnetospheric substorm behavior in the near- and mid-tail region
McPherron, R. L.; Dunlop, M. W.; Baker, D. N.
The Cluster constellation of spacecraft has returned substantial new data on particle and field variations in the near- and mid-magnetotail regions of Earth's magnetosphere. Using the Research with Adaptive Particle Imaging Detectors (RAPID) system onboard the four Cluster vehicles, we have identified substorm-related energetic ( E > 20 keV) el…
Reverse convection and cusp proton aurora: Cluster, polar and image observation
Zong, Q. -G.; Daly, P. W.; Mende, S. B. +4 more
On April 21, 2001 an interplanetary CME started to interact with the magnetosphere when CLUSTER spacecraft were travelling in the cusp region. This interaction produced a strong magnetic storm ( Dst = 103 nT) at Earth. Cusp proton aurora was caused by the leading phase of the CME. Cusp proton aurora generally appear during northward IMF…
Improvement of plasma measurements onboard Cluster due to spacecraft potential control
Escoubet, C. P.; Dandouras, I.; André, M. +6 more
The ion emitter experiment ASPOC (Active Spacecraft Potential Control) and the plasma electron experiment PEACE (Plasma Electron And Current Experiment) have been operating together in a large variety of plasma environments. Three cases on February 4, 2001, May 21, 2002, and June 12, 2002 have been analysed. A clear improvement of the electron mea…
What is Cluster telling us about magnetotail dynamics?
Nakamura, Rumi; Baumjohann, Wolfgang
In this review, we report on some new aspects of magnetotail dynamics found in the data of the first traversal of the magnetotail by the Cluster quartet in summer and autumn 2001: (1) The electron drift instrument made the first direct measurements of tail lobe convection. The statistical data shows convection toward the center of the plasma sheet…
Energetic particle acceleration during a major magnetic storm
Grande, M.; Baker, D.; Blake, J. B. +6 more
We study the global properties of energetic (>30 keV) particles during the main and early recovery phase of a major magnetic storm of March 31, 2001, using data of the NOAA 15 and 16 and the CLUSTER satellites. During the storm main phase the ring current energetic electron and ion fluxes were increased by nearly two orders of magnitude, and th…