Search Publications
Local structure of the magnetotail current sheet: 2001 Cluster observations
Sauvaud, J. -A.; Balogh, A.; Zhang, T. L. +10 more
Thirty rapid crossings of the magnetotail current sheet by the Cluster spacecraft during July-October 2001 at a geocentric distance of 19 RE are examined in detail to address the structure of the current sheet. We use four-point magnetic field measurements to estimate electric current density; the current sheet spatial scale is estimate…
Cluster observations of reconnection due to the Kelvin-Helmholtz instability at the dawnside magnetospheric flank
Balogh, A.; Lavraud, B.; Kistler, L. M. +4 more
On 3 July 2001, the four Cluster satellites traversed along the dawnside magnetospheric flank and observed large variations in all plasma parameters. The estimated magnetopause boundary normals were oscillating in the z-direction and the normal component of the magnetic field showed systematic 2-3 min bipolar variations for 1 h when the IMF had a …
Survey of large-amplitude flapping motions in the midtail current sheet
Nakamura, R.; Sergeev, V. A.; Baumjohann, W. +5 more
<P style="line-height: 20px;"> We surveyed fast current sheet crossings (flapping motions) over the distance range 10-30 RE in the magnetotail covered by the Geotail spacecraft. Since the local tilts of these dynamic sheets are large and variable in these events, we compare three different methods of evaluating current sheet norma…
The structure of flux transfer events recovered from Cluster data
Balogh, A.; Klecker, B.; Owen, C. J. +4 more
The structure and formation mechanism of a total of five Flux Transfer Events (FTEs), encountered on the equatorward side of the northern cusp by the Cluster spacecraft, with separation of ~5000 km, are studied by applying the Grad-Shafranov (GS) reconstruction technique to the events. The technique generates a magnetic field/plasma map of the FTE…
A statistical analysis of the location and width of Saturn's southern auroras
Badman, S. V.; Cowley, S. W. H.; Gérard, J. -C. +1 more
A selection of twenty-two Hubble Space Telescope images of Saturn's ultraviolet auroras obtained during 1997-2004 has been analysed to determine the median location and width of the auroral oval, and their variability. Limitations of coverage restrict the analysis to the southern hemisphere, and to local times from the post-midnight sector to just…
Oscillatory magnetic flux tube slippage in the plasma sheet
Petrukovich, A. A.; Balogh, A.; Zhang, T. L. +4 more
Cluster observations in the magnetotail revealed an abundance of strongly inclined current sheets. We determine the magnetic configuration of a particular subset of such phenomena: a series of sheet crossings, having significantly differing inclinations and occurring during quiet conditions. These wave-like variations appear to propagate azimuthal…
Electron velocity distribution and lion roars in the magnetosheath
Fazakerley, A. N.; Maksimovic, M.; Schwartz, S. J. +1 more
Whistler waves which are termed "lion roars" in the magnetosheath are studied using data obtained by the Spectrum Analyser (SA) of the Spatio-Temporal Analysis of Field Fluctuations (STAFF) experiment aboard Cluster. Kinetic theory is then employed to obtain the theoretical expression for the whistler wave with electron temperature anisotropy whic…
The auroral and ionospheric flow signatures of dual lobe reconnection
Milan, S. E.; Imber, S. M.; Hubert, B.
We present the first substantial evidence for the occurrence of dual lobe reconnection from ionospheric flows and auroral signatures. The process of dual lobe reconnection refers to an interplanetary magnetic field line reconnecting with lobe field lines in both the northern and southern hemispheres. Two bursts of sunward plasma flow across the no…
Characteristics of high altitude oxygen ion energization and outflow as observed by Cluster: a statistical study
Lundin, R.; Yamauchi, M.; Sauvaud, J. -A. +14 more
The results of a statistical study of oxygen ion outflow using Cluster data obtained at high altitude above the polar cap is reported. Moment data for both hydrogen ions (H+) and oxygen ions (O+) from 3 years (2001-2003) of spring orbits (January to May) have been used. The altitudes covered were mainly in the range 5-12 R
Electric field measurements on Cluster: comparing the double-probe and electron drift techniques
André, M.; Klecker, B.; Quinn, J. +9 more
The four Cluster satellites each carry two instruments designed for measuring the electric field: a double-probe instrument (EFW) and an electron drift instrument (EDI). We compare data from the two instruments in a representative sample of plasma regions. The complementary merits and weaknesses of the two techniques are illustrated. EDI operation…