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Cassini/CAPS observations of duskside tail dynamics at Saturn
Thomsen, M. F.; Wilson, R. J.; Tokar, R. L. +2 more
properties of Saturn's premidnight tail region are surveyed using Cassini/Cassini Plasma Spectrometer (CAPS) ion observations from 2010. Only low-latitude (|lat| < 6°) intervals in which the CAPS viewing was roughly symmetric inward and outward around the corotation direction are used. Our numerical moments algorithm returns nonzero ion density…
Multi-instrument observations from Svalbard of a traveling convection vortex, electromagnetic ion cyclotron wave burst, and proton precipitation associated with a bow shock instability
Lavraud, B.; Yeoman, T. K.; Clausen, L. B. N. +12 more
An isolated burst of 0.35 Hz electromagnetic ion cyclotron (EMIC) waves was observed at four sites on Svalbard from 0947 to 0954 UT 2 January 2011, roughly 1 h after local noon. This burst was associated with one of a series of ~50 nT magnetic impulses observed at the northernmost stations of the IMAGE magnetometer array. Hankasalmi SuperDARN rada…
Simultaneous conjugate observations of small-scale structures in Saturn's dayside ultraviolet auroras: Implications for physical origins
Yeoman, T. K.; Nichols, J. D.; Cowley, S. W. H. +2 more
Small-scale features in Saturn's dayside UV auroras are examined using images obtained on 32 Hubble Space Telescope visits close to Saturn equinox when both northern and southern emissions were simultaneously observed, allowing their interhemispheric conjugacy to be investigated. Eastward-propagating patches in the dawn-to-noon sector were observe…
Multiple bidirectional EMIC waves observed by Cluster at middle magnetic latitudes in the dayside magnetosphere
André, M.; Kistler, L. M.; Lin, R. -L. +4 more
is well accepted that the propagation of electromagnetic ion cyclotron (EMIC) waves are bidirectional near their source regions and unidirectional when away from these regions. The generally believed source region for EMIC waves is around the magnetic equatorial plane. Here we describe a series of EMIC waves in the Pc1 (0.2-5 Hz) frequency band ab…
Ordering of injection events within Saturnian SLS longitude and local time
Gurnett, D. A.; Hospodarsky, G. B.; Kennelly, T. J. +1 more
Periodicities similar to the Saturn kilometric radio (SKR) emissions have been observed throughout the magnetosphere in both the magnetic field and the plasma. An outstanding question is what mechanism links these periodicities between the inner and outer magnetospheres. It had been postulated that the interchange instability, where narrow injecti…
The location of the Earth's magnetopause: A comparison of modeled position and in situ Cluster data
Wild, J. A.; Case, N. A.
Exploiting 8years of magnetic field data from the Cluster mission, we employ an automated magnetopause crossing detection routine to determine the magnetopause location over varying magnetic latitudes and local times. For a period spanning nearly one solar cycle we build a database of 2709 magnetopause crossings and compare these locations to the …
Ion temperature anisotropy instabilities in planetary magnetosheaths
Lakhina, G. S.; Tsurutani, B. T.; Echer, E. +2 more
There has been a lack of understanding why mirror modes are present in planetary magnetosheaths, at comets, and in the heliosheath. Linear theory indicates that the ion cyclotron instability should dominate over the mirror mode instability in electron-proton plasma. In this paper, we take a new approach. We examine the role of plasma electron temp…
Particle and magnetic field properties of the Saturnian magnetosheath: Presence and upstream escape of hot magnetospheric plasma
Coates, A. J.; Dougherty, M. K.; Thomsen, M. F. +6 more
We analyze plasma, energetic particle, and magnetic field data from all available Cassini passes through the Saturnian magnetosheath between July 2004 and July 2011 and provide a statistical overview of particle and field properties. The results show that magnetosheath plasma has an average number density of ~0.1 cm-3 and a temperature …
Sources of electron pitch angle anisotropy in the magnetotail plasma sheet
Fazakerley, A. N.; Owen, C. J.; Taylor, M. G. G. T. +3 more
We survey the properties of electron pitch angle distributions in the magnetotail plasma sheet at a distance between 15 and 19 RE from the Earth, using data from the Plasma Electron and Current Experiment (PEACE) instrument. We limit our survey to those pitch angle distributions measured when the interplanetary magnetic field (IMF) had …
Current structure and nonideal behavior at magnetic null points in the turbulent magnetosheath
Adrian, M. L.; Wendel, D. E.
The Poincaré index indicates that the Cluster spacecraft tetrahedron entraps a number of 3-D magnetic nulls during an encounter with the turbulent magnetosheath. Previous researchers have found evidence for reconnection at one of the many filamentary current layers observed by Cluster in this region. We find that many of the entrained nulls are al…