Search Publications
High-latitude plasma convection during Northward IMF as derived from in-situ magnetospheric Cluster EDI measurements
Haaland, S. E.; Torbert, R. B.; Quinn, J. M. +4 more
In this study, we investigate statistical, systematic variations of the high-latitude convection cell structure during northward IMF. Using 1-min-averages of Cluster/EDI electron drift observations above the Northern and Southern polar cap areas for six and a half years (February 2001 till July 2007), and mapping the spatially distributed measurem…
Frequencies of wave packets of whistler-mode chorus inside its source region: a case study
Gurnett, D. A.; Pickett, J. S.; Trakhtengerts, V. Y. +5 more
Whistler-mode chorus is a structured wave emission observed in the Earth's magnetosphere in a frequency range from a few hundreds of Hz to several kHz. We investigate wave packets of chorus using high-resolution measurements recorded by the WBD instrument on board the four Cluster spacecraft. A night-side chorus event observed during geomagnetical…
Access of solar wind electrons into the Martian magnetosphere
Barabash, S.; Lundin, R.; Winningham, J. D. +7 more
Electrons with energy of ~40 80 eV measured by the instrument ASPERA-3 on Mars Express and MAG-ER onboard Mars Global Surveyor are used to trace an access of solar wind electrons into the Martian magnetosphere. Crustal magnetic fields create an additional protection from solar wind plasma on the dayside of the Southern Hemisphere by shifting the b…
The statistics of foreshock cavities: results of a Cluster survey
Schwartz, S. J.; Sibeck, D. G.; Billingham, L.
We use Cluster magnetic field, thermal ion, and energetic particle observations upstream of the Earth's bow shock to investigate the occurrence patterns of foreshock cavities. Such cavities are thought to form when bundles of magnetic field connect to the quasi-parallel bow shock. Shock-processed suprathermal ions can then stream along the field, …
Coupled rotational dynamics of Saturn's thermosphere and magnetosphere: a thermospheric modelling study
Smith, C. G. A.; Aylward, A. D.
We use a numerical model of Saturn's thermosphere to investigate the flow of angular momentum from the atmosphere to the magnetosphere. The thermosphere model is driven by Joule heating and ion drag calculated from a simple model of the magnetospheric plasma flows and a fixed model of the ionospheric conductivity. We describe an initial study in w…
First results from ideal 2-D MHD reconstruction: magnetopause reconnection event seen by Cluster
Teh, W. -L.; Ã-. Sonnerup, B. U.
We have applied a new reconstruction method (Sonnerup and Teh, 2008), based on the ideal single-fluid MHD equations in a steady-state, two-dimensional geometry, to a reconnection event observed by the Cluster-3 (C3) spacecraft on 5 July 2001, 06:23 UT, at the dawn-side Northern-Hemisphere magnetopause. The event has been previously studied by use …
On nonstationarity and rippling of the quasiperpendicular zone of the Earth bow shock: Cluster observations
Dudok de Wit, T.; Krasnoselskikh, V. V.; Lobzin, V. V. +1 more
A new method for remote sensing of the quasiperpendicular part of the bow shock surface is presented. The method is based on analysis of high frequency electric field fluctuations corresponding to Langmuir, upshifted, and downshifted oscillations in the electron foreshock. Langmuir waves usually have maximum intensity at the upstream boundary of t…
Observation of three distinct ion populations at the Kelvin-Helmholtz-unstable magnetopause
Lavraud, B.; Taylor, M. G. G. T.
We report Double Star spacecraft observations of the dusk-flank magnetopause and its boundary layer under predominantly northward interplanetary magnetic field (IMF). Under such conditions the flank low-latitude boundary layers (LLBL) of the magnetosphere are known to broaden. The primary candidate processes associated with the transport of solar …
Cluster observations of near-Earth magnetospheric lobe plasma densities a statistical study
Haaland, S.; Lybekk, B.; Pedersen, A. +1 more
The Cluster-mission has enabled a study of the near-Earth magnetospheric lobes throughout the waning part of solar cycle 23. During the first seven years of the mission the satellites crossed this region of space regularly from about July to October. We have obtained new and more accurate plasma densities in this region based on spacecraft potenti…
Dependence of the open-closed field line boundary in Saturn's ionosphere on both the IMF and solar wind dynamic pressure: comparison with the UV auroral oval observed by the HST
Belenkaya, E. S.; Badman, S. V.; Cowley, S. W. H. +2 more
We model the open magnetic field region in Saturn's southern polar ionosphere during two compression regions observed by the Cassini spacecraft upstream of Saturn in January 2004, and compare these with the auroral ovals observed simultaneously in ultraviolet images obtained by the Hubble Space Telescope. The modelling employs the paraboloid model…