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Jupiter cloud morphology and zonal winds from ground-based observations before and during Juno's first perijove
Hueso, R.; Sánchez-Lavega, A.; Rojas, J. F. +8 more
We analyze Jupiter observations between December 2015 and August 2016 in the 0.38-1.7 µm wavelength range from the PlanetCam instrument at the 2.2 m telescope at Calar Alto Observatory and in the optical range by amateur observers contributing to the Planetary Virtual Observatory Laboratory. Over this time Jupiter was in a quiescent state wi…
Ion hole formation and nonlinear generation of electromagnetic ion cyclotron waves: THEMIS observations
Miyoshi, Yoshizumi; Kasahara, Satoshi; Asamura, Kazushi +6 more
Electromagnetic plasma waves are thought to be responsible for energy exchange between charged particles in space plasmas. Such an energy exchange process is evidenced by phase space holes identified in the ion distribution function and measurements of the dot product of the plasma wave electric field and the ion velocity. We develop a method to i…
Investigation of diurnal variability of water vapor in Enceladus' plume by the Cassini ultraviolet imaging spectrograph
Hansen, C. J.; Hendrix, A. R.; Portyankina, G. +4 more
An occultation of ɛ Orionis by Enceladus' plume was observed with Enceladus at an orbital longitude near apoapsis in order to investigate whether water vapor flow is modulated diurnally, similar to ice particles. The occultation showed that the bulk water vapor emanating from Enceladus changes little with orbital position. The amount of gas in at …
Mars Under Primordial Solar Wind Conditions: Mars Express Observations of the Strongest CME Detected at Mars Under Solar Cycle #24 and its Impact on Atmospheric Ion Escape
Barabash, Stas; Nilsson, Hans; Holmström, Mats +3 more
An extremely strong Coronal Mass Ejection (CME) impacted Mars on 12 July 2011, while the Mars Express spacecraft was present inside the nightside ionosphere. Estimated solar wind density and speed during the event are 39 particles cm-3 and 730 km/s, corresponding to nominal solar wind flux at Mars when the solar system was ∼1.1 Ga old. …
Redetection of the Ionospheric H3+ Signature of Saturn's "Ring Rain"
Baines, Kevin H.; O'Donoghue, James; Moore, Luke +4 more
In April 2011 Saturn's midlatitude ionospheric H3+ emissions were detected, exhibiting anomalous (nonsolar) H3+ latitudinal variations consistent with the transport of water from specific locations in Saturn's rings, known as "ring rain". These products, transported to the planet along the magnetic field, may help to explain the unusual pattern of…
Dynamic response of the Martian ionosphere to an interplanetary shock: Mars Express and MAVEN observations
Gurnett, D. A.; Halekas, J. S.; Kopf, A. J. +10 more
Multipoint observations from the Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) instrument on board Mars Express and the Mars Atmosphere and Volatile EvolutioN (MAVEN) mission reveal a dynamic response of the Martian ionosphere to abrupt variations in the upstream solar wind plasma. On 2 February 2017, MAVEN, located upstream …
Venus's winds and temperatures during the MESSENGER's flyby: An approximation to a three-dimensional instantaneous state of the atmosphere
Clancy, R. T.; Hueso, R.; Sánchez-Lavega, A. +14 more
Even though many missions have explored the Venus atmospheric circulation, its instantaneous state is poorly characterized. In situ measurements vertically sampling the atmosphere exist for limited locations and dates, while remote sensing observations provide only global averages of winds at altitudes of the clouds: 47, 60, and 70 km. We present …
Radar sounder evidence of thick, porous sediments in Meridiani Planum and implications for ice-filled deposits on Mars
Grant, John A.; Plaut, Jeffrey J.; Phillips, Roger J. +5 more
Meridiani Planum is one of the most intensely studied regions on Mars, yet little is known about the physical properties of the deposits below those examined by the Opportunity rover. We report the detection of subsurface echoes within the Meridiani Planum deposits from data obtained by the Mars Advanced Radar for Subsurface and Ionospheric Soundi…
Growth rate measurement of ULF waves in the ion foreshock
Hietala, H.; Angelopoulos, V.; Dorfman, S. +1 more
We report the first satellite measurement of the ultralow frequency (ULF) wave growth rate in the upstream region of the Earth's bow shock. We employ the two identical ARTEMIS spacecraft orbiting the Moon to characterize crescent-shaped reflected ion beams and relatively monochromatic ULF waves. The event presented here features spacecraft separat…
The interplanetary magnetic field observed by Juno enroute to Jupiter
Connerney, John E. P.; Gruesbeck, Jacob R.; Gershman, Daniel J. +1 more
The Juno spacecraft was launched on 5 August 2011 and spent nearly 5 years traveling through the inner heliosphere on its way to Jupiter. The Magnetic Field Investigation was powered on shortly after launch and obtained vector measurements of the interplanetary magnetic field (IMF) at sample rates from 1 to 64 samples/second. The evolution of the …