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Heliospheric Conditions at Saturn During Cassini's Ring-Grazing and Proximal Orbits
DOI: 10.1029/2018GL078093 Bibcode: 2018GeoRL..4510812R

Krupp, N.; Jackman, C. M.; Roussos, E. +6 more

We surveyed energetic charged particle measurements by Cassini between 2016 and the end of the mission in order to identify transients of solar energetic particles and galactic cosmic rays. Such transients offer hints about the state of the heliosphere and valuable context for interpreting space weather phenomena in Saturn's magnetosphere. The per…

2018 Geophysical Research Letters
Cassini 12
Extremely Low-Frequency Waves Inside the Diamagnetic Cavity of Comet 67P/Churyumov-Gerasimenko
DOI: 10.1029/2017GL076415 Bibcode: 2018GeoRL..45.3854M

Gunell, H.; Eriksson, A.; Karlsson, T. +7 more

The European Space Agency/Rosetta mission to comet 67P/Churyumov-Gerasimenko has provided several hundred observations of the cometary diamagnetic cavity induced by the interaction between outgassed cometary particles, cometary ions, and the solar wind magnetic field. Here we present the first electric field measurements of four preperihelion and …

2018 Geophysical Research Letters
Rosetta 11
Saturn's Innermost Radiation Belt Throughout and Inward of the D-Ring
DOI: 10.1029/2018GL077954 Bibcode: 2018GeoRL..4510912K

Krupp, N.; Roussos, E.; Mitchell, D. G. +6 more

Cassini discovered Saturn's innermost radiation belt during the end of its mission. The belt is populated with relativistic protons, probably up to the trapping limit of ≈20 GeV. It extends from Saturn's dense atmosphere into and throughout the D-ring. The A-C rings separate this belt entirely from the previously known radiation belts, suggesting …

2018 Geophysical Research Letters
Cassini 9
Photometric Modeling and VIS-IR Albedo Maps of Dione From Cassini-VIMS
DOI: 10.1002/2017GL076869 Bibcode: 2018GeoRL..45.2184F

Buratti, B. J.; Clark, R. N.; Stephan, K. +6 more

We report about visible and infrared albedo maps and spectral indicators of Dione's surface derived from the complete Visual and Infrared Mapping Spectrometer (VIMS) data set acquired between 2004 and 2017 during the Cassini tour in Saturn's system. Maps are derived by applying a photometric correction necessary to disentangle the intrinsic albedo…

2018 Geophysical Research Letters
Cassini 8
Energetic Neutral and Charged Particle Measurements in the Inner Saturnian Magnetosphere During the Grand Finale Orbits of Cassini 2016/2017
DOI: 10.1029/2018GL078096 Bibcode: 2018GeoRL..4510847K

Krupp, N.; Dougherty, M. K.; Roussos, E. +6 more

We give an overview of the charged and neutral particle measurements during the Grand Finale of Cassini performed by the Magnetosphere Imaging Instrument, MIMI, on board. The first in situ measurements of MeV particles between the D-ring and the atmosphere of the planet showed protons with energies above 300 MeV with higher count rates when magnet…

2018 Geophysical Research Letters
Cassini 8
Saturn's Planetary Period Oscillations During the Closest Approach of Cassini's Ring-Grazing Orbits
DOI: 10.1029/2018GL077925 Bibcode: 2018GeoRL..45.4692H

Dougherty, M. K.; Cowley, S. W. H.; Provan, G. +2 more

Saturn's planetary period oscillations (PPOs) are ubiquitous throughout its magnetosphere. We investigate the PPO's azimuthal magnetic field amplitude interior to the field-aligned currents, during the closest approaches of Cassini's ring-grazing orbits (October 2016 to April 2017), with periapses at 2.5 RS. The amplitudes of the northe…

2018 Geophysical Research Letters
Cassini 8
Cassini CAPS Identification of Pickup Ion Compositions at Rhea
DOI: 10.1002/2017GL076588 Bibcode: 2018GeoRL..45.1704D

Coates, A. J.; Thomsen, M. F.; Jones, G. H. +9 more

Saturn's largest icy moon, Rhea, hosts a tenuous surface-sputtered exosphere composed primarily of molecular oxygen and carbon dioxide. In this Letter, we examine Cassini Plasma Spectrometer velocity space distributions near Rhea and confirm that Cassini detected nongyrotropic fluxes of outflowing CO2+ during both the R1 and R1.5 encounters. Accou…

2018 Geophysical Research Letters
Cassini 8
Photometric Modeling and VIS-IR Albedo Maps of Tethys From Cassini-VIMS
DOI: 10.1029/2018GL078602 Bibcode: 2018GeoRL..45.6400F

Clark, R. N.; Stephan, K.; D'Aversa, E. +6 more

We report about the derivation of visible (VIS) and infrared (IR) albedo maps and spectral indicators of Saturn's satellite Tethys from the complete Cassini-Visual and Infrared Mapping Spectrometer (VIMS) data set. The application of a photometric correction is necessary to remove illumination and viewing effects from the I/F spectra, to compute s…

2018 Geophysical Research Letters
Cassini 7
First Observation of Lion Roar Emission in Saturn's Magnetosheath
DOI: 10.1002/2017GL075919 Bibcode: 2018GeoRL..45..486P

Gurnett, D. A.; Hospodarsky, G. B.; Kurth, W. S. +3 more

We present an observation of intense emissions in Saturn's magnetosheath as detected by the Cassini spacecraft. The emissions are observed in the dawn sector (magnetic local time ∼06:45) of the magnetosheath over a time period of 11 h before the spacecraft crossed the bow shock and entered the unshocked solar wind. They are found to be narrow-band…

2018 Geophysical Research Letters
Cassini 6
The Eye of Saturn's North Polar Vortex: Unexpected Cloud Structures Observed at High Spatial Resolution by Cassini/VIMS
DOI: 10.1029/2018GL078168 Bibcode: 2018GeoRL..45.5867B

Sotin, C.; Brown, R. H.; Baines, K. H. +6 more

Near-infrared spectral maps of Saturn's north polar vortex obtained at high spatial resolution provided by Cassini/Visual Infrared Mapping Spectrometer (VIMS) reveal localized ammonia clouds composed of unusually large particles exceeding 13 µm in radius, the largest cloud particles documented during the Cassini mission. Taken under near-opt…

2018 Geophysical Research Letters
Cassini 6