Search Publications
Dimensional analysis of observed structures using multipoint magnetic field measurements: Application to Cluster
Balogh, A.; Zhang, H.; Zong, Q. -G. +6 more
A new method is described to analyze the dimensional character of observed structures using multipoint magnetic field measurements of four or more spacecraft. The technique can provide three directions along which the magnetic field has the minimum, intermediate, and maximum derivatives if the magnetic gradient tensor G = $\nabla$$\vec{B at every …
Cluster encounter of a magnetic reconnection diffusion region in the near-Earth magnetotail on September 19, 2003
Balogh, A.; Rème, H.; Mouikis, C. +7 more
We report a clear encounter by the Cluster spacecraft of a magnetic reconnection diffusion region in the near-Earth magnetotail at XGSM = -17.5 RE on September 19, 2003. In addition to the reversals of the plasma jets and of GSM-z (~normal) component of the magnetic field, clear signatures of Hall quadrupolar (GSM-y) magnetic…
Observations of multiple X-line structure in the Earth's magnetotail current sheet: A Cluster case study
Balogh, A.; Dandouras, I.; Eastwood, J. P. +7 more
Observations of the Earth's magnetotail made by the four Cluster spacecraft on October 2 2003 are presented. Multi-spacecraft analysis is used to show that the variations in field and flow observed in the vicinity of the magnetotail current sheet are most consistent with a series of two active reconnection sites bounding an Earthward moving flux r…
Global cooling and densification of the plasma sheet during an extended period of purely northward IMF on October 22-24, 2003
Wing, S.; Balogh, A.; Fujimoto, M. +6 more
The October 22-24, 2003 interplanetary magnetic cloud was characterized by an exceptionally long interval (~32 hours) of nearly purely northward interplanetary magnetic field (IMF). Following the northward IMF turning Cluster observed a gradual transition to a cold (<1 keV) and dense (~1-2 cm-3) plasma sheet (CDPS). Cluster observed …
Plasma sheet formation during long period of northward IMF
Phan, Tai D.; Øieroset, Marit; Raeder, Joachim +2 more
We have studied the entry paths of solar wind plasma into the magnetosphere during an extended period of northward IMF using an OpenGGCM MHD simulation of the cold dense plasma sheet (CDPS) event observed on October 23, 2003 by the Cluster spacecraft. We find that high-latitude reconnection occurs tailward of both cusps between the IMF and geomagn…
How typical are atypical current sheets?
Balogh, A.; Zhang, T. L.; Klecker, B. +7 more
Using multi-satellite Cluster magnetic field data, we statistically examined how often an atypical, i.e., non-Harris type, current sheet is formed. We found that a cross-tail current sheet with an off-equatorial current density maximum, indicating bifurcation, is frequently formed in thin current sheets with a half thickness of ~1500 km. The occur…
Electron anisotropy constraint in the magnetosheath: Cluster observations
Lavraud, Benoit; Gary, S. Peter; Thomsen, Michelle F. +2 more
The whistler anisotropy instability is driven by the condition T$\perp$e/T$\parallel$e > 1, where the subscript e denotes electrons and the other subscripts denote directions relative to the background magnetic field Bo. Instability growth leads to enhanced field fluctuations which scatter the electrons; theory …
Ion sound wave packets at the quasiperpendicular shock front
Krasnoselskikh, V.; Dunlop, M.; Fazakerley, A. +6 more
Electric field measurements from a single spacecraft have been used to study ion-sound turbulence observed within the Earth's bow shock. The observed frequency of the ion-sound waves can be both lower and higher than the local electron cyclotron frequency depending upon the direction of wave propagation in the plasma rest frame. The ion-sound wave…
New features of electron diffusion regions observed at subsolar magnetic field reconnection sites
Bale, S. D.; Torbert, R. B.; McFadden, J. P. +1 more
Nineteen electron diffusion regions at magnetic field reconnection sites have been found in one hour of Cluster satellite data near the subsolar magnetopause. Investigations on previously unachieved spatial and temporal scales show the following for the first time: direct conversion of magnetic energy to electron energy (The resulting accelerated …
Plasmoid in the high latitude boundary/cusp region observed by Cluster
Balogh, A.; Glassmeier, K. -H.; Zhang, H. +8 more
A plasmoid-like structure without a core magnetic field has been observed by Cluster spacecraft in the high latitude magnetopause region when the interplanetary magnetic field (IMF) is northward and has a dominant duskward component. Bursty electrons and ions are found to be well confined in this plasmoid-like structure. The structure possesses a …