Search Publications
Polar cap ion beams during periods of northward IMF: Cluster statistical results
Dandouras, I.; de Keyser, J.; Maggiolo, R. +3 more
Above the polar caps and during prolonged periods of northward IMF, the Cluster satellites detect upward accelerated ion beams with energies up to a few keV. They are associated with converging electric field structures indicating that the acceleration is caused by a quasi-static field-aligned electric field that can extend to altitudes higher tha…
Ducted propagation of chorus waves: Cluster observations
Walker, S. N.; Yearby, K. H.; Khotyaintsev, Yu. V. +4 more
Ducted propagation of whistler waves in the terrestrial magnetosphere-ionosphere system was discussed and studied long before the first in-situ spacecraft measurements. While a number of implicit examples of the existence of ducted propagation have been found, direct observation of ducts has been hampered by the low sampling rates of measurements …
Three-dimensional spatial structures of solar wind turbulence from 10 000-km to 100-km scales
Glassmeier, K. -H.; Sahraoui, F.; Goldstein, M. L. +2 more
Using the four Cluster spacecraft, we have determined the three-dimensional wave-vector spectra of fluctuating magnetic fields in the solar wind. Three different solar wind intervals of Cluster data are investigated for this purpose, representing three different spatial scales: 10 000 km, 1000 km, and 100 km. The spectra are determined using the w…
Electric field variability and classifications of Titan's magnetoplasma environment
Arridge, C. S.; Achilleos, N.; Guio, P.
The atmosphere of Saturn's largest moon Titan is driven by photochemistry, charged particle precipitation from Saturn's upstream magnetosphere, and presumably by the diffusion of the magnetospheric field into the outer ionosphere, amongst other processes. Ion pickup, controlled by the upstream convection electric field, plays a role in the loss of…
Comparison of three methods for the estimation of cross-shock electric potential using Cluster data
Balikhin, M. A.; Dimmock, A. P.; Hobara, Y.
Cluster four point measurements provide a comprehensive dataset for the separation of temporal and spatial variations, which is crucial for the calculation of the cross shock electrostatic potential using electric field measurements. While Cluster is probably the most suited among present and past spacecraft missions to provide such a separation a…
Occurrence rate of magnetic holes between 0.72 and 1 AU: comparative study of Cluster and VEX data
Zhang, T. L.; Walker, S. N.; Amariutei, O. A.
Localised depressions in the magnetic field magnitude, or magnetic holes, are common features in many regions of solar system plasma. Two distinct mechanisms for their generation have been proposed. The first proposed that the structures are generated locally, close to the point of observation. The alternative has been proposed by Russell et al. (…
On large plasmoid formation in a global magnetohydrodynamic simulation
Janhunen, P.; Palmroth, M.; Honkonen, I. +2 more
We investigate plasmoid formation in the magnetotail using the global magnetohydrodynamic (MHD) simulation GUMICS-4. Here a plasmoid implies a major reconfiguration of the magnetotail where a part of the tail plasma sheet is ejected downstream, in contrast to small Earthward-propagating plasmoids. We define a plasmoid based solely on the structure…
Anomalous foreshock field-aligned beams observed by Cluster
Mazelle, C.; Wilber, M.; Meziane, K. +2 more
We report occasional observations of two simultaneously distinct ion foreshock components recorded by the Cluster spacecraft upstream of the Earth's bow shock. In most occurrences, the lower-energy population originates as a field-aligned beam (FAB) associated with quasi-perpendicular regions, which loses energy as the IMF rotates into oblique geo…
Impact of solar wind depression on the dayside magnetosphere under northward interplanetary magnetic field
Ben-Jaffel, L.; Baraka, S.
We present a follow up study of the sensitivity of the Earth's magnetosphere to solar wind activity using a particles-in-cell model (Baraka and Ben Jaffel, 2007), but here during northward Interplanetary Magnetic Field (IMF). The formation of the magnetospheric cavity and its elongation around the planet is obtained with the classical structure of…
Spatial dependence of magnetopause energy transfer: Cluster measurements verifying global simulations
Dandouras, I.; Lucek, E. A.; Dunlop, M. +4 more
We investigate the spatial variation of magnetopause energy conversion and transfer using Cluster spacecraft observations of two magnetopause crossing events as well as using a global magnetohydrodynamic (MHD) simulation GUMICS-4. These two events, (16 January 2001, and 26 January 2001) are similar in all other aspects except for the sign of the i…