Search Publications
Local structure of directional discontinuities in the solar wind
Haaland, S. E.; Paschmann, G.; Teh, W. -L. +1 more
We examine local structures of three directional discontinuities (DDs) observed by Cluster in the solar wind, using reconstruction based on the ideal 2-D MHD equations in a steady state. In this novel application of the technique, our goals are the following: (1) to explain why the minimum variance analysis of the magnetic field (MVAB) often fails…
SAPS intensification during substorm recovery: A multi-instrument case study
Nishimura, Y.; Lyons, L. R.; Kellerman, A. C. +3 more
A case of the major intensification of the subauroral polarization stream (SAPS) during the substorm recovery phase is presented. The continuous high-time-resolution Doppler velocity measurements in the subauroral and auroral regions were conducted with the Unwin HF radar, and these are analyzed in the context of the simultaneous and coincident me…
Peak electron densities in Saturn's ionosphere derived from the low-frequency cutoff of Saturn lightning
Gurnett, D. A.; Fischer, G.; Zarka, P. +2 more
Radio bursts from Saturn lightning have been observed by the Cassini Radio and Plasma Wave Science instrument at frequencies of a few megahertz during several month-long storms since 2004. As the radio waves traverse Saturn's ionosphere on their way to the spacecraft, one can determine the peak electron density from the measurement of the low-freq…
Dual-spacecraft observation of large-scale magnetic flux ropes in the Martian ionosphere
Gurnett, D. A.; Winningham, J. D.; Frahm, R. A. +5 more
We here report the first dual-spacecraft detection of planetary flux ropes in the ionosphere of Mars. The Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS), on board Mars Express, can measure the magnetic field magnitude near the spacecraft. Typically, these measurements track the known crustal magnetic field strength very well; …
Evolution in space and time of the quasi-static acceleration potential of inverted-V aurora and its interaction with Alfvénic boundary processes
Lucek, E.; Nilsson, H.; Karlsson, T. +8 more
Results are presented from Cluster crossings of the acceleration region of two inverted-V auroras located in the poleward part of an extensive substorm bulge. The particle and field data are used to infer the acceleration potentials of the arcs and their distribution in altitude and latitude. The C1 data are consistent with a symmetric potential p…
The plasma environment of Titan: The magnetodisk of Saturn near the encounters as derived from ion densities measured by the Cassini/CAPS plasma spectrometer
Thomsen, M.; Szego, K.; Nemeth, Z. +3 more
We analyze ion densities derived from the data of the Cassini Plasma Spectrometer for the time period of the prime mission till the end of May 2008, in the low latitude outer magnetosphere near Titan encounters. We have found that the central line of the magnetodisk is surrounded by a structured plasma sheet, a smooth, broad ion layer composed of …
The implications of the H2 variability in Titan's exosphere
Galand, M.; Yelle, R. V.; Cui, J. +2 more
We present in this paper an investigation of the distribution of H2 in Titan's exosphere, based on the measurements made with the Ion Neutral Mass Spectrometer (INMS) onboard Cassini during 32 encounters with the satellite. The observed H2 density in Titan's exosphere shows significant variance from flyby to flyby. However, n…
Midnight sector observations of auroral omega bands
Lucek, E.; Wild, J. A.; Woodfield, E. E. +14 more
We present observations of auroral omega bands on 28 September 2009. Although generally associated with the substorm recovery phase and typically observed in the morning sector, the features presented here occurred just after expansion phase onset and were observed in the midnight sector, dawnward of the onset region. An all-sky imager located in …
Modeling of Cassini's charging at Saturn orbit insertion flyby
Yaroshenko, V. V.; Miloch, W. J.; Thomas, H. M. +2 more
Spacecraft-plasma interactions are studied in the regime relevant for Cassini during the Saturn orbit insertion (SOI) flyby. Three-dimensional particle-in-cell self-consistent code has been employed to calculate the spacecraft potential in a complicated plasma environment of Saturn's magnetosphere for a wide range of distances (for dipole shells b…
Energy conversion at the Earth's magnetopause using single and multispacecraft methods
Dandouras, I.; Lucek, E.; Haaland, S. E. +3 more
We present a small statistical data set, where we investigate energy conversion at the magnetopause using Cluster measurements of magnetopause crossings. The Cluster observations of magnetic field, plasma velocity, current density and magnetopause orientation are needed to infer the energy conversion at the magnetopause. These parameters can be in…