Search Publications
Control of periodic variations in Saturn's magnetosphere by compressional waves
Kivelson, Margaret Galland; Jia, Xianzhe
Many of the periodic variations observed in Saturn's magnetosphere can be linked directly to the presence of a rotating pattern of field-aligned currents that link the northern and southern ionospheres with each other and with the magnetosphere. Such a current system is incorporated in a magnetohydrodynamic simulation that has previously been show…
Polar confinement of Saturn's magnetosphere revealed by in situ Cassini observations
Coates, A. J.; Dougherty, M. K.; Masters, A. +4 more
Plasma rotation plays a large role in determining the size and shape of Saturn's disk-like magnetosphere. A magnetosphere more confined to the equator in the polar regions is expected as a result of the interaction between this type of obstacle and the solar wind. In addition, at times away from equinox, a north-south asymmetry is expected where t…
Keogram analysis of ENA images at Saturn
Mitchell, D. G.; Carbary, J. F.
Keograms are constructed from azimuthal profiles of energetic hydrogen atoms (25-55 keV) from Saturn's magnetosphere. The keograms exhibit linear structures or "tracks" that reveal prograde rotational motion of features or "blobs" in the energetic neutral atom (ENA) images. From polynomial fits, the first derivatives of these tracks are used to es…
The extension of ionospheric holes into the tail of Venus
Fedorov, A.; Barabash, S.; Holmström, M. +8 more
Ionospheric holes are Cytherian nightside phenomena discovered by the NASA Pioneer Venus Orbiter, featuring localized plasma depletions driven by prominent and unexplained enhancements in the draped interplanetary magnetic field. Observed only during solar maximum, the phenomenon remains unexplained, despite their frequent observation during the f…
Solar filament impact on 21 January 2005: Geospace consequences
Escoubet, C. P.; Tsurutani, B. T.; Cattell, C. +21 more
On 21 January 2005, a moderate magnetic storm produced a number of anomalous features, some seen more typically during superstorms. The aim of this study is to establish the differences in the space environment from what we expect (and normally observe) for a storm of this intensity, which make it behave in some ways like a superstorm. The storm w…
The plasma depletion layer in Saturn's magnetosheath
Coates, A. J.; Russell, C. T.; Dougherty, M. K. +5 more
A plasma depletion layer (PDL) of reduced plasma density and enhanced magnetic field strength can form in the magnetosheath (shocked solar wind) adjacent to the magnetopause boundary of a planetary magnetosphere. The dominant factor controlling the level of plasma depletion and field enhancement in Earth's PDL is the magnetic shear across the magn…
On the identification of time interval threshold in the twin-CME scenario
Li, Gang; Ding, Liu-Guan; Jiang, Yong +3 more
Recently it has been suggested that the "twin-CME" scenario may be a very effective mechanism in causing extreme solar energetic particle (SEP) events and, in particular, ground level enhancement (GLE) events. Ding et al. (2013) performed a statistical examination of the twin-CME scenario with a total of 126 fast and wide western coronal mass ejec…
Observation of a retreating x line and magnetic islands poleward of the cusp during northward interplanetary magnetic field conditions
Fuselier, S. A.; Trattner, K. J.; Eriksson, S. +3 more
When the interplanetary magnetic field is northward, reconnection occurs in each hemisphere on lobe field lines, poleward of the cusp. We have identified a case where the Cluster spacecraft crossed the magnetopause and encountered a tailward retreating x line. The x line is identified by the encounter of both a tailward and sunward jet, as well as…
Isothermal magnetosheath electrons due to nonlocal electron cross talk
Schwartz, S. J.; Mitchell, J. J.
Heating of the various plasma species at the Earth's collisionless bow shock is not fully understood. Although the total amount of heating is constrained by the one-fluid Rankine-Hugoniot relations in terms of local plasma conditions, the partition of energy between, e.g., electrons and ions, is influenced by particle kinetics which are not consid…
The magnetic structure of Saturn's magnetosheath
Dougherty, M. K.; Jia, X.; Masters, A. +1 more
A planet's magnetosheath extends from downstream of its bow shock up to the magnetopause, where the solar wind flow is deflected around the magnetosphere and the solar wind-embedded magnetic field lines are draped. This makes the region an important site for plasma turbulence, instabilities, reconnection, and plasma depletion layers. A relatively …