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Subsidence of Ionospheric Flows Triggered by Magnetotail Magnetic Reconnection During Transpolar Arc Brightening
Pu, Zu-Yin; Fu, Sui-Yan; Shi, Quan-Qi +8 more
A transpolar arc (TPA), which extended from postmidnight to prenoon, was seen on 16 September 2001 in the Northern Hemisphere under northward interplanetary magnetic field (IMF)-Bz and weakly dawnward IMF-By conditions. Super Dual Auroral Radar Network detected significant westward plasma flows just equatorward of the polewar…
The Quasi-monochromatic ULF Wave Boundary in the Venusian Foreshock: Venus Express Observations
Zhang, Tielong; Mazelle, Christian; Lu, Quanming +5 more
The location of ultralow-frequency (ULF) quasi-monochromatic wave onset upstream of Venus bow shock is explored using Venus Express magnetic field data. We report the existence of a spatial foreshock boundary behind which ULF waves are present. We have found that the ULF wave boundary at Venus is sensitive to the interplanetary magnetic field (IMF…
On the Role of Ionospheric Ions in Sawtooth Events
Kistler, L. M.; Frey, H. U.; Lund, E. J. +2 more
Simulations have suggested that feedback of heavy ions originating in the ionosphere is an important mechanism for driving sawtooth injections. However, this feedback may only be necessary for events driven by coronal mass ejections (CMEs), whereas in events driven by streaming interaction regions (SIRs), solar wind variability may suffice to driv…
Identifying 3-D Vortex Structures At/Around the Magnetopause Using a Tetrahedral Satellite Configuration
Lembège, B.; Hasegawa, H.; Cai, D. +1 more
Identifying vortices is the key to understanding the turbulence in plasma shear layers. This paper aims to provide general guidelines for identifying 3-D vortex structures. Currently, no single precise definition of a vortex is universally accepted, despite the significance of vortices in fluid and plasma dynamics. Recently, various vortex identif…
Oxygen Ion Reflection at Earthward Propagating Dipolarization Fronts in the Magnetotail
Parks, G. K.; Sun, W. J.; Fu, S. Y. +7 more
A dipolarization front (DF) is known as the leading edge of an earthward high-speed flow with a sharp enhancement in the northward magnetic field (Bz). Analysis of an event observed by Cluster shows that the behavior of oxygen ions (O+) around the DF is very different from protons (H+). After the crossing of the DF…
Four-Spacecraft Magnetic Curvature and Vorticity Analyses on Kelvin-Helmholtz Waves in MHD Simulations
Lavraud, Benoit; Kieokaew, Rungployphan; Foullon, Claire
Four-spacecraft missions are probing the Earth's magnetospheric environment with high potential for revealing spatial and temporal scales of a variety of in situ phenomena. The techniques allowed by these four spacecraft include the calculation of vorticity and the magnetic curvature analysis (MCA), both of which have been used in the study of var…
On the Asymmetry Between Upward and Downward Field-Aligned Currents Interacting With the Ionosphere
Streltsov, A. V.
The paper presents results from the numerical study of the magnetosphere-ionosphere interactions driven by the large-scale electric field in the magnetically conjugate, high-latitude regions of northern and southern hemispheres. Simulations of the two-fluid MHD model demonstrate that these interactions can lead to a generation of a system of small…
Saturn's Northern Auroras and Their Modulation by Rotating Current Systems During Late Northern Spring in Early 2014
Lamy, L.; Badman, S. V.; Cowley, S. W. H. +3 more
The Hubble Space Telescope imaged Saturn's northern ultraviolet auroras during February-June 2014, when Saturn's northern and southern magnetic perturbation fields were locked in antiphase and matched in rotation period ( 10.69 hr). During this coalescence period, we test for evidence of rotational modulation of the auroras using the latest rotati…
Properties of the HPS-ICME-CIR Interaction Event of 9-10 September 2011
Morgan, Huw; Al-Shakarchi, Duraid A.
During 9-10 September 2011 the ACE, Wind, and SOHO spacecraft measured the complex interaction between an interplanetary coronal mass ejection (ICME) and a corotating interaction region (CIR) associated with the heliospheric sector boundary. Except for a few short periods, the suprathermal electrons are unidirectional, suggesting that the ICME mag…
The Periodic Flapping and Breathing of Saturn's Magnetodisk During Equinox
Dougherty, M. K.; Arridge, C. S.; Guio, P. +3 more
Periodic variations have been observed in many field and particle properties in Saturn's magnetosphere, modulated at a period close to the planetary rotation rate. Magnetic field observations by Cassini's magnetometer instrument suggest that in the outer magnetosphere (beyond ∼12 Saturn radii) Saturn's current sheet is periodically displaced with …