Search Publications
Current sheet structure near magnetic X-line observed by Cluster
Balogh, A.; Zhang, T. L.; Klecker, B. +9 more
During the interval 0947-0951 UT on 1 October 2001, when Cluster was located at X GSM = -16.4 R E near Z GSM = 0 in the pre-midnight magnetotail, the Cluster barycenter crosses the neutral sheet four times. High speed proton flow, with reversal from tailward to Earthward, was detected during the crossings. Us…
Current sheet flapping motion and structure observed by Cluster
Balogh, A.; Zhang, T. L.; André, M. +8 more
Fast vertical flapping oscillations of the plasma sheet have been observed by Cluster on September 26, 2001. The flapping motion had vertical speeds exceeding 100 km/s, an amplitude in excess of 1 RE and a quasiperiod of ~3 min. The current sheet was mostly tilted in the Y-Z plane (with the tilt sometimes exceeding 45°). The waves had t…
Cluster observation of a bifurcated current sheet
Balogh, A.; Zhang, T. L.; Nakamura, R. +4 more
The current sheet structure and motion at XGSM = -19.5 RE, observed by Cluster/FGM during 1055-1107 UT on 29 August 2001, is examined. It is found that during the interval 1055-1102 UT the current sheet moves vertically up and down with a velocity of about 60 km/s. During this interval the current sheet has a bifurcated struc…
Simultaneous Cluster and IMAGE observations of cusp reconnection and auroral proton spot for northward IMF
Lundin, R.; Sauvaud, J. -A.; Balogh, A. +22 more
On March 18, 2002, under northward interplanetary magnetic field (IMF) and high (~15 nPa) solar wind dynamic pressure conditions, Cluster observed reconnection signatures and the passage of an X-line at the large (~175°) magnetic-shear high-latitude magnetopause (MP). The observations are consistent with the occurrence of a reconnection site tailw…
Transverse dimensions of chorus in the source region
Gurnett, D. A.; Santolík, O.
We report measurement of whistler-mode chorus by the four Cluster spacecraft at close separations. We focus our analysis on the generation region close to the magnetic equatorial plane at a radial distance of 4.4 Earth's radii. We use both linear and rank correlation analysis to define perpendicular dimensions of the sources of chorus elements bel…
Cluster electric current density measurements within a magnetic flux rope in the plasma sheet
Balogh, A.; Owen, C. J.; Reme, H. +11 more
On August 22, 2001 all 4 Cluster spacecraft nearly simultaneously penetrated a magnetic flux rope in the tail. The flux rope encounter took place in the central plasma sheet, βi ~ 1-2, near the leading edge of a bursty bulk flow. The ``time-of-flight'' of the flux rope across the 4 spacecraft yielded Vx ~ 700 km/s and a diame…
Simulation of energetic particle injections associated with a substorm on August 27, 2001
Baker, D. N.; Sarris, T. E.; Peterson, W. K. +2 more
Discrete injections of energetic electrons and ions and their subsequent drift echoes were observed shortly after 0410 UT on August 27, 2001 by three geosynchronous satellites which were arrayed on the dayside. The GOES-8 spacecraft at geosynchronous orbit near local midnight, the four-satellite CLUSTER constellation also near local midnight. Conc…
Kink mode oscillation of the current sheet
Balogh, A.; Zhang, T. L.; Glassmeier, K. -H. +6 more
Oscillations of the current sheet observed by the Cluster spacecraft are investigated, using the special ability of Cluster to separate between spatial and temporal variations. We find that before substorm onset, a thin current sheet moves with a velocity of 10 km/s mainly in the vertical direction; after substorm onset the current sheet thickens …
Dispersion analysis of ULF waves in the foreshock using cluster data and the wave telescope technique
Dandouras, I.; Glassmeier, K. -H.; Rème, H. +6 more
Cluster provides us with a unique possibility to study ULF waves. We analyze ULF wave activity in the near-Earth upstream solar wind. Using Cluster as a wave telescope we investigate in detail wave propagation directions and wave numbers for various frequencies, obtaining, for the first time, three dimensional dispersion relations experimentally. …
Magnetic mirror structures observed by Cluster in the magnetosheath
Glassmeier, K. -H.; Treumann, R.; Constantinescu, O. D. +1 more
We present a method for identification of magnetic mirror structures (MMS) in multi-point spacecraft measurements and for deriving their full 3D geometry. Multiple minima in magnetic field data are no longer regarded as separate MMS but as belonging to the same mirror structure. The approach is based on fitting a model magnetic field to measured d…