Search Publications
Effect of a northward turning of the interplanetary magnetic field on cusp precipitation as observed by Cluster
Berchem, J.; Escoubet, C. P.; Pitout, F. +10 more
The immediate effect of the rotation of the interplanetary magnetic field (IMF) from southward to northward on cusp precipitation has been rarely observed by a polar orbiting satellite in the past. The four Cluster spacecraft observed such an event on 23 September 2004 as they were crossing the polar cusp within 2-16 min from each other. Between t…
Cyclic behavior of solar full-disk activity
Li, K. J.; Gao, P. X.; Li, Q. X. +1 more
In order to describe the cyclic behavior of solar full-disk activity (the surface magnetic fields, filaments, the green Fe XIV, 5303Å corona local maxima intensities, and torsional oscillations), we propose a new concept, a "full-disk activity cycle," which consists of two successive normal cycles: a high-latitude activity cycle following a low-la…
Multispacecraft observation of electron beam in reconnection region
Escoubet, C. P.; Lavraud, B.; Fazakerley, A. N. +6 more
On the 18th of August 2002, during a crossing of the near-Earth plasma sheet Cluster observed an ion flow burst, caused by a near-Earth reconnection event. Cluster observed a tailward bulk flow which reverse to earthward flow, indicating a close passage of the diffusion region. We show that reversals in BZ and BY are consiste…
Shock propagation in the magnetosphere: Observations and MHD simulations compared
Laitinen, T. V.; Pulkkinen, T. I.; AndréEová, K. +1 more
We examine the propagation of disturbances in the Earth's magnetosphere caused by fast forward shock interaction with the magnetopause. Our statistical study and event analyses show that the propagation speeds are larger in the magnetosphere than in the solar wind and are larger in the nightside magnetosphere than in the dayside magnetosphere. A c…
Near-Earth substorm features from multiple satellite observations
Zhang, T. L.; RèMe, H.; Fazakerley, A. N. +12 more
We investigate a substorm on 3 October 2004 during which 11 satellites were located in near-Earth magnetotail (XGSM > -10 RE). Double Star 1 (TC-1), Cluster, and LANL-97 satellites were closely aligned in the dawn-dusk direction (<1 RE apart) for this conjunction. After substorm expansion onset, TC-1 observed…
Interplanetary coronal mass ejections that are undetected by solar coronagraphs
Simnett, G. M.; Howard, T. A.
From February 2003 to September 2005 the Solar Mass Ejection Imager on the Coriolis spacecraft detected 207 interplanetary coronal mass ejections (ICME) in the inner heliosphere. We have examined the data from the Large Angle Spectroscopic Coronagraph (LASCO) on the SOHO spacecraft for evidence of coronal transient activity that might have been th…
Wave activity inside hot flow anomaly cavities
Dandouras, I.; Lucek, E. A.; Tjulin, A.
Low-frequency wave properties inside two hot flow anomalies (HFAs) at different stages of evolution are, for the first time, studied applying the k-filtering technique on multipoint measurements from the Cluster satellites. The observed wave activity in an HFA cavity in an early stage of its evolution was interpreted as the combination of inherent…
Cluster observations of fast shocks in the magnetosheath launched as a tangential discontinuity with a pressure increase crossed the bow shock
Farrugia, C. J.; RèMe, H.; Dunlop, M. +6 more
The interaction of a tangential discontinuity (TD) and accompanying dynamic pressure increase with the Earth's bow shock launches a fast shock that travels ahead of the TD in the magnetosheath and carries a significant portion of the pressure change. In this event study, we use observations from the Cluster spacecraft and magnetohydrodynamic simul…
Heating Titan's upper atmosphere
de La Haye, V.; Waite, J. H.; Cravens, T. E. +3 more
A detailed analysis of the mechanisms heating Titan's neutral atmosphere is provided. Two primary sources of incoming energy, the solar photons and the energetic electrons from Saturn's magnetosphere, are taken into account. The processes studied include the excitation of atmospheric molecules by electron impact, suprathermal electron heating, and…
Posteruptive phenomena in coronal mass ejections and substorms: Indicators of a universal process?
Webb, D. F.; Wiltberger, M.; Schwadron, N. A. +8 more
We examine phenomena associated with eruptions in the two different regimes of the solar corona and the terrestrial magnetosphere. We find striking similarities between the speeds of shrinking magnetic field lines in the corona and dipolarization fronts traversing the magnetosphere. We also examine the similarities between supra-arcade downflows o…