Search Publications
Electric structure of dipolarization front at sub-proton scale
André, M.; Vaivads, A.; Huang, S. Y. +2 more
Using Cluster data, we investigate the electric structure of a dipolarization front (DF) - the ion inertial length (c/ωpi) scale boundary in the Earth's magnetotail formed at the front edge of an earthward propagating flow with reconnected magnetic flux. We estimate the current density and the electron pressure gradient throughout the D…
Occurrence rate of earthward-propagating dipolarization fronts
André, M.; Vaivads, A.; Huang, S. Y. +2 more
The occurrence rate of earthward-propagating dipolarization fronts (DFs) is investigated in this paper based on the 9 years (2001-2009) of Cluster 1 data. For the first time, we select the DF events by fitting the characteristic increase in Bz using a hyperbolic tangent function. 303 earthward-propagating DFs are found; they have on ave…
Recent advances in understanding substorm dynamics
Nakamura, R.; Sergeev, V. A.; Angelopoulos, V.
Magnetospheric substorms are elemental processes of solar wind energy storage and explosive release in Earth's magnetosphere. They encompass fundamental plasma physics questions, are ubiquitous during all types of geomagnetic conditions, contribute significantly to magnetic storms, and are a key element of Space Weather applications. This paper re…
Low-energy ions: A previously hidden solar system particle population
André, M.; Cully, C. M.
Ions with energies less than tens of eV originate from the Terrestrial ionosphere and from several planets and moons in the solar system. The low energy indicates the origin of the plasma but also severely complicates detection of the positive ions onboard sunlit spacecraft at higher altitudes, which often become positively charged to several tens…
Electron acceleration in the reconnection diffusion region: Cluster observations
André, M.; Vaivads, A.; Sahraoui, F. +10 more
We present one case study of magnetic islands and energetic electrons in the reconnection diffusion region observed by the Cluster spacecraft. The cores of the islands are characterized by strong core magnetic fields and density depletion. Intense currents, with the dominant component parallel to the ambient magnetic field, are detected inside the…
Auroral evidence of Io's control over the magnetosphere of Jupiter
Bonfond, B.; Clarke, J. T.; Gérard, J. -C. +5 more
Contrary to the case of the Earth, the main auroral oval on Jupiter is related to the breakdown of plasma corotation in the middle magnetosphere. Even if the root causes for the main auroral emissions are Io's volcanism and Jupiter's fast rotation, changes in the aurora could be attributed either to these internal factors or to fluctuations of the…
Dielectric map of the Martian northern hemisphere and the nature of plain filling materials
Pommerol, Antoine; Kofman, Wlodek; Clifford, Stephen M. +2 more
A number of observations suggest that an extended ocean once covered a significant part of the Martian northern hemisphere. By probing the physical properties of the subsurface to unprecedented depth, the MARSIS/Mars Express provides new geophysical evidences for the former existence of a Late Hesperian ocean. The Vastitas Borealis formation, loca…
The importance of plasma β conditions for magnetic reconnection at Saturn's magnetopause
Coates, A. J.; Russell, C. T.; Dougherty, M. K. +7 more
Magnetic reconnection is an important process that occurs at the magnetopause boundary of Earth's magnetosphere because it leads to transport of solar wind energy into the system, driving magnetospheric dynamics. However, the nature of magnetopause reconnection in the case of Saturn's magnetosphere is unclear. Based on a combination of Cassini spa…
Enceladus' extreme heat flux as revealed by its relaxed craters
Singer, Kelsi N.; Schenk, Paul M.; McKinnon, William B. +1 more
Enceladus' cratered terrains contain large numbers of unusually shallow craters consistent with deformation by viscous relaxation of water ice under conditions of elevated heat flow. Here we use high-resolution topography to measure the relaxation fraction of craters on Enceladus far from the active South Pole. We find that many craters are shallo…
Observations of turbulence within reconnection jet in the presence of guide field
André, M.; Vaivads, A.; Sahraoui, F. +8 more
We present the first comprehensive observations of turbulence properties within high speed reconnection jet in the plasma sheet with moderate guide field. The power spectral density index is about -1.73 in the inertial range, and follows the value of -2.86 in the ion dissipation range. The turbulence is strongly anisotropic in the wave-vector spac…