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Characterization of auroral current systems in Saturn's magnetosphere: High-latitude Cassini observations
Coates, A. J.; Dougherty, M. K.; Cowley, S. W. H. +3 more
We have identified seven periapsis passes during the first high-latitude phase of the Cassini mission, from mid-2006 to mid-2007, in which the spacecraft traversed at intermediate altitudes the region between open field lines at highest latitudes and the region inside the inner edge of the ring current. Varying azimuthal magnetic fields indicative…
Tailward and earthward flow onsets observed by Cluster in a thin current sheet
Petrukovich, A. A.; RèMe, H.; Nakamura, R. +1 more
From a Cluster survey of the magnetotail during 2001-2007 we select 49 episodes of thin current sheet observations ending with plasma sheet activity onsets. The onsets were defined as flow bursts and/or electric current decrease and/or Bz increase after a period of local quietness (in many cases with signatures of growth phase). Such on…
Time-dependent global MHD simulations of Cassini T32 flyby: From magnetosphere to magnetosheath
Coates, A. J.; Russell, C. T.; Dougherty, M. K. +10 more
When the Cassini spacecraft flew by Titan on 13 June 2007, at 13.6 Saturn local time, Titan was directly observed to be outside Saturn's magnetopause. Cassini observations showed dramatic changes of magnetic field orientation as well as other plasma flow parameters during the inbound and outbound segments. In this paper, we study Titan's ionospher…
Reliability of prediction of the magnetosheath BZ component from interplanetary magnetic field observations
Němeček, Z.; Gutynska, O.; Šafránková, J. +2 more
In the present statistical study, we discuss a probability of simultaneous observations of the same sign of the magnetic field BZ component in the solar wind and magnetosheath. The analysis is based on 5 min data from four spacecraft (Interball-1, IMP 8, Cluster, and THEMIS) operating in different phases of the solar cycle in the magnet…
Excess open solar magnetic flux from satellite data: 1. Analysis of the third perihelion Ulysses pass
Lockwood, M.; Owens, M.; Rouillard, A. P.
We use the third perihelion pass by the Ulysses spacecraft to illustrate and investigate the “flux excess” effect, whereby open solar flux estimates from spacecraft increase with increasing heliocentric distance. We analyze the potential effects of small-scale structure in the heliospheric field (giving fluctuations in the radial component on time…
Thickness of Saturn's ring current determined from north-south Cassini passes through the current layer
Coates, A. J.; Cowley, S. W. H.; Bunce, E. J. +1 more
We investigate magnetic field and plasma electron data from six Cassini orbits during which, unique within the mission to date, the spacecraft passed almost directly north-south through Saturn's equatorial plane within the ring current region of the middle magnetosphere. Three passes took place in the postnoon sector and three took place in the po…
Cluster observations of the entry layer equatorward of the cusp under northward interplanetary magnetic field
Zhang, H.; Zong, Q. -G.; Lucek, E. +11 more
Various boundary crossings in the vicinity of the high-altitude cusp region were experienced by the Cluster spacecraft when the interplanetary magnetic field (IMF) was northward. In contrast to the southward IMF cases, in which a turbulent and diffusive entry layer is present equatorward of the cusp, a transition layer (without significant turbule…
A comparison of the formation and evolution of magnetic flux ropes in solar coronal mass ejections and magnetotail plasmoids
Moldwin, M. B.; Linton, M. G.
Solar coronal mass ejections and their interplanetary counterparts often show evidence of a twisted flux rope structure that is nearly identical, though of vastly different spatial scale, to plasmoids observed in the Earth's magnetotail. This paper reviews the current understanding of flux rope formation, morphology, and evolution in coronal mass …
Statistical analysis of earthward flow bursts in the inner plasma sheet during substorms
Zhang, T. L.; Dandouras, I.; Lucek, E. +5 more
In this article, we study the velocity distribution, density, duration, and energy transport of earthward flow bursts in the inner plasma sheet (IPS) during three substorm phases using the data of Cluster in 2001 and 2002. The mean peak velocity of earthward flow bursts in recovery phases (390 km/s) is smaller than those in growth and expansion ph…
Transient auroral features at Saturn: Signatures of energetic particle injections in the magnetosphere
Krupp, N.; Roussos, E.; Mitchell, D. G. +7 more
We report for the first time transient isolated auroral spots at Saturn's southern polar region, based on Hubble Space Telescope (HST) FUV images. The spots last several minutes and appear distinct from the rest of the auroral emissions. We study two sets of HST and Cassini observations during which Cassini instrumentation detected signatures of e…