Search Publications
Motion of the dipolarization front during a flow burst event observed by Cluster
Balogh, A.; Zhang, T. L.; Dandouras, I. +12 more
In this paper we study a flow burst event which took place during enhanced geomagnetic activity on July 22, 2001, when Cluster was located in the postmidnight magnetotail. The flow burst was associated with a clear dipolarization ahead of the high-speed part of the predominantly Earthward directed flow. Based on the analysis of the four spacecraft…
The solar wind composition throughout the solar cycle: A continuum of dynamic states
Zurbuchen, T. H.; Gloeckler, G.; Fisk, L. A. +1 more
Variations in the speed and elemental and ionic charge composition of the solar wind are reported throughout the solar cycle, as observed by the SWICS instrument on Ulysses. The apparent bimodal nature of the solar wind during the solar minimum does not persist throughout the solar cycle. Rather, with increasing solar activity, a continuum of sola…
A wavy twisted neutral sheet observed by CLUSTER
Balogh, A.; Zhang, T. L.; Glassmeier, K. -H. +2 more
From July to October 2001, the Cluster satellites were located within the magnetotail and crossings of the neutral sheet were frequently observed by the FGM instrument [Balogh et al., 2001]. The neutral sheet often appears to be moving relative to the spacecraft. Multiple crossings of the neutral sheet on August 3, 2001 are analysed. These neutral…
Fast flow during current sheet thinning
Balogh, A.; Zhang, T. L.; Klecker, B. +9 more
In this paper we report Cluster observation of a fast flow event in the plasma sheet associated with a small auroral substorm intensification at 1838 UT on August 12, 2001. Cluster, located in the plasma sheet, experienced significant thinning of the current sheet associated with a high-speed Earthward flow of 900 km/s. By using the four spacecraf…
Saturn: Search for a missing water source
Johnson, R. E.; Jurac, S.; Richardson, J. D. +3 more
The origin of the large hydroxyl radical (OH) cloud near the inner moons of Saturn, indicative of a surprisingly large water-vapor source, has represented a puzzle since its discovery in 1992. A new set of Hubble Space Telescope measurements is used to constrain the OH spatial densities and to pinpoint the source region. Our model indicates that t…
Timing of magnetic reconnection initiation during a global magnetospheric substorm onset
Daly, P. W.; Dunlop, M. W.; Baker, D. N. +13 more
We have used a unique constellation of Earth-orbiting spacecraft and ground-based measurements in order to study a relatively isolated magnetospheric substorm event on August 27, 2001. Global ultraviolet images of the northern auroral region established the substorm expansion phase onset at 0408:19 (+/-1 min) UT. Concurrent measurements from the G…
Density modulated whistler mode emissions observed near the plasmapause
Santolik, O.; Parrot, M.; Andre, M. +4 more
Electron density fluctuations are regularly observed near the plasmapause together with electromagnetic waves below the electron cyclotron frequency (usually called hiss or chorus). Instruments on board CLUSTER spacecraft often observe two such emission bands with fluctuating wave intensities that suggest wave ducting in density enhancements as we…
Ulysses' second fast-latitude scan: Complexity near solar maximum and the reformation of polar coronal holes
Balogh, A.; Reisenfeld, D. B.; McComas, D. J. +5 more
Ulysses' second fast latitude scan, near solar maximum, comprises a complicated mixture of solar wind flows from a variety of sources at high southern as well as low heliolatitudes. In contrast, observations northward of ~40° N show the reformation of relatively steady fast solar wind flows, which are virtually indistinguishable from the polar cor…
Cluster observations of the exterior cusp and its surrounding boundaries under northward IMF
Lundin, R.; Sauvaud, J. -A.; Escoubet, C. P. +18 more
We have studied in detail multi-spacecraft observations of the exterior cusp on 04 February 2001, during a steady northward Interplanetary Magnetic Field (IMF) interval. At a radial distance of 11 Re, Cluster encountered a well-bounded region where the magnetic field exhibited very low diamagnetic values and the ions displayed high levels of isotr…
Phase-steepened Alfvén waves, proton perpendicular energization and the creation of magnetic holes and magnetic decreases: The ponderomotive force
Lakhina, G. S.; Tsurutani, B. T.; Goldstein, B. E. +6 more
Solar wind protons detected within Magnetic Holes (MHs) and Magnetic Decreases (MDs) are found to be preferentially heated perpendicular to B0. The MHs/MDs are associated with the phase-steepened edges of nonlinear Alfvén waves. The proton anisotropies can lead to the proton cyclotron and mirror mode plasma instabilities. We examine the…