Search Publications
High-latitude plasma convection from Cluster EDI measurements: method and IMF-dependence
Haaland, S. E.; Torbert, R. B.; Quinn, J. M. +6 more
We have used vector measurements of the electron drift velocity made by the Electron Drift Instrument (EDI) on Cluster between February 2001 and March 2006 to derive statistical maps of the high-latitude plasma convection. The EDI measurements, obtained at geocentric distances between ~4 and ~20 RE over both hemispheres, are mapped into…
Dynamics of thin current sheets: Cluster observations
Sauvaud, J. -A.; Vaivads, A.; Le Contel, O. +9 more
The paper tries to sort out the specific signatures of the Near Earth Neutral Line (NENL) and the Current Disruption (CD) models, and looks for these signatures in Cluster data from two events. For both events transient magnetic signatures are observed, together with fast ion flows. In the simplest form of NENL scenario, with a large-scale two-dim…
Multi-spacecraft observation of plasma dipolarization/injection in the inner magnetosphere
Sauvaud, J. -A.; Daly, P. W.; Khotyaintsev, Y. +13 more
Addressing the origin of the energetic particle injections into the inner magnetosphere, we investigate the 23 February 2004 substorm using a favorable constellation of four Cluster (near perigee), LANL and Geotail spacecraft. Both an energy-dispersed and a dispersionless injection were observed by Cluster crossing the plasma sheet horn, which map…
Motion of flux transfer events: a test of the Cooling model
Dandouras, I.; Fazakerley, A. N.; Daly, P. W. +7 more
The simple model of reconnected field line motion developed by Cooling et al. (2001) has been used in several recent case studies to explain the motion of flux transfer events across the magnetopause. We examine 213 FTEs observed by all four Cluster spacecraft under a variety of IMF conditions between November 2002 and June 2003, when the spacecra…
Cluster observations of a field aligned current at the dawn flank of a bursty bulk flow
Pitout, F.; Klecker, B.; Hasegawa, H. +9 more
This article describes observations of a bursty bulk flow (BBF) in the outer central plasma sheet. The observations are made with the Cluster satellites, located approximately 19 RE downtail, close to the midnight sector in the Southern Hemisphere. 40-60 s after Cluster first detected the BBF, there was a large bipolar perturbation in t…
Ion multi-nose structures observed by Cluster in the inner Magnetosphere
Sauvaud, J. -A.; Escoubet, C. P.; Dandouras, I. +7 more
During the last 30 years, several magnetospheric missions have recorded the presence of narrow proton structures in the ring current region. These structures have been referred as "nose-like" structures, due to their appearance when represented in energy-time spectrograms, characterized by a flux value increase for a narrow energy range.
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Multi-scale observations of magnetotail flux transport during IMF-northward non-substorm intervals
Owen, C. J.; Nakamura, R.; Takada, T. +7 more
Simultaneous observations by the Cluster spacecraft and SuperDARN radars are presented of magnetotail flux transport during northward, but BY-dominated IMF. Two events are discussed, which occurred on 14 August 2004 and 17 September 2005, during intervals of negative and positive IMF BY, respectively. During both intervals th…
High-latitude plasma convection from Cluster EDI: variances and solar wind correlations
Haaland, S. E.; Torbert, R. B.; Quinn, J. M. +4 more
Based on drift velocity measurements of the EDI instruments on Cluster during the years 2001-2006, we have constructed a database of high-latitude ionospheric convection velocities and associated solar wind and magnetospheric activity parameters. In an earlier paper (Haaland et al., 2007), we have described the method, consisting of an improved te…
Spatial and temporal characteristics of poloidal waves in the terrestrial plasmasphere: a CLUSTER case study
Pierrard, V.; Glassmeier, K. H.; Blomberg, L. G. +3 more
Oscillating magnetic field lines are frequently observed by spacecraft in the terrestrial and other planetary magnetospheres. The CLUSTER mission is a very suitable tool to further study these Alfvén waves as the four CLUSTER spacecraft provide for an opportunity to separate spatial and temporal structures in the terrestrial magnetosphere. Using a…
Least-squares gradient calculation from multi-point observations of scalar and vector fields: methodology and applications with Cluster in the plasmasphere
Dunlop, M. W.; de Keyser, J.; Décréau, P. M. E. +1 more
This paper describes a general-purpose algorithm for computing the gradients in space and time of a scalar field, a vector field, or a divergence-free vector field, from in situ measurements by one or more spacecraft. The algorithm provides total error estimates on the computed gradient, including the effects of measurement errors, the errors due …