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First Observations of the Disruption of the Earth's Foreshock Wave Field During Magnetic Clouds
Escoubet, C. P.; Dandouras, I.; Palmroth, M. +8 more
The foreshock, extending upstream of Earth's bow shock, is a region of intense electromagnetic wave activity and nonlinear phenomena, which can have global effects on geospace. It is also the first geophysical region encountered by solar wind disturbances journeying toward Earth. Here, we present the first observations of considerable modification…
Energetic Oxygen and Sulfur Charge States in the Outer Jovian Magnetosphere: Insights From the Cassini Jupiter Flyby
Wilson, R. J.; Krimigis, S. M.; Mitchell, D. G. +10 more
On 10 January 2001, Cassini briefly entered into the magnetosphere of Jupiter, en route to Saturn. During this excursion into the Jovian magnetosphere, the Cassini Magnetosphere Imaging Instrument/Charge-Energy-Mass Spectrometer detected oxygen and sulfur ions. While Charge-Energy-Mass Spectrometer can distinguish between oxygen and sulfur charge …
Spectral Signatures of Adiabatic Electron Acceleration at Saturn Through Corotation Drift Cancelation
Krupp, N.; Roussos, E.; Zong, Q. G. +3 more
The energetic electron spectra of Saturn's radiation belts are studied using Cassini's 13 years of measurements by the Magnetosphere Imaging Instrument/Low Energy Magnetospheric Measurement System detector. We find that between L shells (L) of 10 and 4.5 the differential flux spectrum of 0.3- to 1.6-MeV electrons evolves from a single power law to…
The Dynamics of Saturn's Main Aurorae
Badman, S. V.; Ray, L. C.; Cowley, S. W. H. +9 more
Saturn's main aurorae are thought to be generated by plasma flow shears associated with a gradient in angular plasma velocity in the outer magnetosphere. Dungey cycle convection across the polar cap, in combination with rotational flow, may maximize (minimize) this flow shear at dawn (dusk) under strong solar wind driving. Using imagery from Cassi…
Migrating Scarps as a Significant Driver for Cometary Surface Evolution
Soderblom, J. M.; Davidsson, B.; Oklay, N. +10 more
Rosetta observations of 67P/Churyumov-Gerasimenko (67P) reveal that most changes occur in the fallback-generated smooth terrains, vast deposits of granular material blanketing the comet's northern hemisphere. These changes express themselves both morphologically and spectrally across the nucleus, yet we lack a model that describes their formation …
IMF By Influence on Magnetospheric Convection in Earth's Magnetotail Plasma Sheet
Hamrin, M.; Tenfjord, P.; Laundal, K. M. +7 more
We use Geotail, Cluster, and Time History of Events and Macroscale Interactions during Substorms data over 15 years (1995-2009) to statistically investigate convective ion flows (V⊥xy<200 km/s) in the magnetotail plasma sheet under the influence of a clearly nonzero dawn-dusk interplanetary magnetic field (IMF By). We find…
Morphology and Dynamics of Venus's Middle Clouds With Akatsuki/IR1
Hueso, R.; Sánchez-Lavega, A.; Kardasis, E. +8 more
The Venusian atmosphere is covered by clouds with superrotating winds whose accelerating mechanism is still not well understood. The fastest winds, occurring at the cloud tops (∼70-km height), have been studied for decades, thanks to their visual contrast in dayside ultraviolet images. The middle clouds (∼50-55 km) can be observed at near-infrared…
Observations on a Series of Merging Magnetic Flux Ropes Within an Interplanetary Coronal Mass Ejection
Zhao, Yan; Feng, Hengqiang; Zhao, Guoqing +2 more
Coronal mass ejections (CMEs) are intense solar explosive eruptions. CMEs are highly important players in solar-terrestrial relationships, and they have important consequences for major geomagnetic storms and energetic particle events. It has been unclear how CMEs evolve when they propagate in the heliosphere. Here we report an interplanetary CME …
The Rocky-Like Behavior of Cometary Landslides on 67P/Churyumov-Gerasimenko
Bertaux, Jean-Loup; Da Deppo, Vania; Naletto, Giampiero +36 more
Landslides have been identified on several solar system bodies, and different mechanisms have been proposed to explain their runout length. We analyze images from the Rosetta mission and report the global characterization of such features on comet 67P/Churyumov-Gerasimenko's surface. By assuming the height to runout length as an approximation for …
Impact of Data Assimilation on Thermal Tides in the Case of Venus Express Wind Observation
Sugimoto, Norihiko; Takagi, Masahiro; Kouyama, Toru
Impacts of horizontal winds assimilation on thermal tides are investigated by using the Venus atmospheric general circulation model for the Earth Simulator local ensemble transform Kalman filter data assimilation system. The assimilated data are horizontal winds derived from Venus ultraviolet images taken by the Venus Monitoring Camera onboard the…