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Caldera Collapse and Volcanic Resurfacing in Arabia Terra Provide Hints of Vast Under-Recognized Early Martian Volcanism
Michalski, Joseph R.; Wright, Shawn P.; Chu, Yin Yau Yoyo +1 more
Arabia Terra is an ancient, geologically complex region of Mars. It is not typically described as volcanic because it lacks prominent, easily recognizable shield volcanoes. However, Arabia Terra contains flood lavas and widespread layered materials that might represent airfall pyroclastics from unknown sources. Here we explore the geology of some …
Titan's Global Radiant Energy Budget During the Cassini Epoch (2004-2017)
West, Robert A.; Nixon, Conor A.; Fry, Patrick M. +5 more
Radiant energies of planets and moons are of wide interest in the fields of geoscience and planetary science. Based on long-term multiinstrument observations from the Cassini spacecraft, we provide here the first observational study of Titan's global radiant energy budget and its seasonal variations. Our results show that Titan's radiant energy bu…
Properties of Plasmoids Observed in Saturn's Dayside and Nightside Magnetodisc
Coates, A. J.; Wei, Y.; Ye, S. -Y. +7 more
Plasmoid is a key structure for transferring magnetic flux and plasma in planetary magnetospheres. At Earth, plasmoids are key media which transfer energy and mass in the "Dungey Cycle." For giant planets, plasmoids are primarily generated by the dynamic processes associated with "Vasyliunas cycle." It is generally believed that planetary magnetot…
The Micro-Macro Coupling of Mass-Loading in Symmetric Magnetic Reconnection With Cold Ions
Hesse, Michael; Spinnangr, Susanne F.; Tenfjord, Paul +4 more
We investigate how magnetic reconnection is influenced by an inflow of a dense cold ion population. We compare two 2.5D Particle-In-Cell simulations, one containing the cold population and one without. We find that the cold population influences the reconnection process on both global and kinetic scales, and that the dominant contribution can be e…
The Cushion Region and Dayside Magnetodisc Structure at Saturn
Dougherty, M. K.; Masters, A.; Achilleos, N. +1 more
A sustained quasi dipolar magnetic field between the current sheet outer edge and the magnetopause, known as a cushion region, has previously been observed at Jupiter, but not yet at Saturn. Using the complete Cassini magnetometer data, the first evidence of a cushion region forming at Saturn is shown. Only five examples of a sustained cushion are…
Lower Surface Temperature at Bright Ephemeral Feature Site on Titan's North Pole
Barnes, Jason W.; Dhingra, Rajani D.; Cottini, Valeria +1 more
We report a temperature difference in one of the regions on Titan that is, documented as a bright ephemeral feature (BEF). Spectra were recorded by Cassini's Composite Infrared Spectrometer. BEFs are 5 µm bright areas that appear, disappear, and shift from flyby to flyby at Titan's North Pole observed in Visual and Infrared Mapping Spectrometer (V…
Interaction of Saturn's Hexagon With Convective Storms
Hueso, R.; Sánchez-Lavega, A.; Barry, T. +8 more
In March 2020, a convective storm erupted at planetographic latitude 76°N in the southern flank of Saturn's long lived hexagonal wave. The storm reached a zonal size of 4,500 km and developed a tail extending zonally 33,000 km. Two new short lived storms erupted in May in the hexagon edge. These storms formed after the convective storms that took …
Explanation for the Increase in High-Altitude Water on Mars Observed by NOMAD During the 2018 Global Dust Storm
Aoki, S.; Vandaele, A. C.; Daerden, F. +21 more
The Nadir and Occultation for MArs Discovery (NOMAD) instrument on board ExoMars Trace Gas Orbiter measured a large increase in water vapor at altitudes in the range of 40-100 km during the 2018 global dust storm on Mars. Using a three-dimensional general circulation model, we examine the mechanism responsible for the enhancement of water vapor in…
Global Model of Whistler Mode Chorus in the Near-Equatorial Region (|λm|< 18°)
Shen, Xiao-Chen; Meredith, Nigel P.; Horne, Richard B. +2 more
We extend our database of whistler mode chorus, based on data from seven satellites, by including ∼3 years of data from Radiation Belt Storm Probes (RBSP)-A and RBSP-B and an additional ∼6 years of data from Time History of Events and Macroscale Interactions during Substorms (THEMIS)-A, THEMIS-D, and THEMIS-E. The new database allows us to probe t…
Flux Erosion of Magnetic Clouds by Reconnection With the Sun's Open Flux
Nandy, Dibyendu; Pal, Sanchita; Dash, Soumyaranjan
Magnetic clouds (MCs) are flux rope magnetic structures forming a subset of solar coronal mass ejections, which have significant space weather impacts. The geoeffectiveness of MCs depends on their properties, which evolve during their interplanetary passage. Based on an analysis of observations spanning two solar cycles, we establish that MCs inte…