Search Publications
Do Deltas Along the Crustal Dichotomy Boundary of Mars in the Gale Crater Region Record a Northern Ocean?
Rivera-Hernández, Frances; Palucis, Marisa C.
Deltaic deposits mapped along the Martian crustal dichotomy boundary scarp have been suggested to delineate an ancient ocean in the northern lowlands of Mars. Using recently acquired orbital data, we have expanded the dichotomy delta inventory and performed an updated analysis of delta front elevations, a proxy for paleo-water levels. Our analysis…
On the Relation Between Jovian Aurorae and the Loading/Unloading of the Magnetic Flux: Simultaneous Measurements From Juno, Hubble Space Telescope, and Hisaki
Kurth, W. S.; Bagenal, F.; Yoshioka, K. +20 more
We present simultaneous observations of aurorae at Jupiter from the Hubble Space Telescope and Hisaki, in combination with the in situ measurements of magnetic field, particles, and radio waves from the Juno Spacecraft in the outer magnetosphere, from 80RJ to 60RJ during 17 to 22 March 2017. Two cycles of accumulation and rel…
The Methane Diurnal Variation and Microseepage Flux at Gale Crater, Mars as Constrained by the ExoMars Trace Gas Orbiter and Curiosity Observations
Atreya, Sushil K.; Newman, Claire E.; Moores, John E. +8 more
The upper bound of 50 parts per trillion by volume for Mars methane above 5 km established by the ExoMars Trace Gas Orbiter, substantially lower than the 410 parts per trillion by volume average measured overnight by the Curiosity Rover, places a strong constraint on the daytime methane flux at the Gale crater. We propose that these measurements m…
Electron Vorticity Indicative of the Electron Diffusion Region of Magnetic Reconnection
Russell, C. T.; Khotyaintsev, Y.; Hasegawa, H. +17 more
While vorticity defined as the curl of the velocity has been broadly used in fluid and plasma physics, this quantity has been underutilized in space physics due to low time resolution observations. We report Magnetospheric Multiscale (MMS) observations of enhanced electron vorticity in the vicinity of the electron diffusion region of magnetic reco…
Alfvén Wave Propagation in the Io Plasma Torus
Bagenal, F.; Bonfond, B.; Hinton, P. C.
Io, the most volcanically active body in the solar system, fuels a plasma torus around Jupiter with dissociation products of SO2 at a rate of 1,000 kg/s. We use a combination of in situ Voyager 1 data and Cassini Ultraviolet Imaging Spectrograph observations to constrain a diffusive equilibrium model of the Io plasma torus. The interact…
The Ion Composition of Saturn's Equatorial Ionosphere as Observed by Cassini
Kurth, W. S.; Wahlund, J. -E.; Waite, J. H. +5 more
The Cassini Orbiter made the first in situ measurements of the upper atmosphere and ionosphere of Saturn in 2017. The Ion and Neutral Mass Spectrometer (INMS) found molecular hydrogen and helium as well as minor species including water, methane, ammonia, and organics. INMS ion mode measurements of light ion species (H+, H2
Understanding Cassini RPWS Antenna Signals Triggered by Dust Impacts
Hospodarsky, G. B.; Kurth, W. S.; Zaslavsky, A. +11 more
Electric field antennas are capable of detecting dust impacts in different space environment. We analyze the dust impact signals detected by the Cassini Radio and Plasma Wave Science instrument at different locations around Saturn and compare them with dust impact signals simulated in laboratory conditions and numerically. The spacecraft potential…
Saturn's Ionosphere: Electron Density Altitude Profiles and D-Ring Interaction From The Cassini Grand Finale
Persoon, A. M.; Kurth, W. S.; Wahlund, J. -E. +8 more
We present the electron density (ne) altitude profiles of Saturn's ionosphere at near-equatorial latitudes from all 23 orbits of Cassini's Grand Finale. The data are collected by the Langmuir probe part of the Radio and Plasma Wave Science investigation. A high degree of variability in the electron density profiles is observed. However,…
C-Complex Asteroids: UV-Visible Spectral Characteristics and Implications for Space Weathering Effects
Vilas, Faith; Hendrix, Amanda R.
Space weathering effects on the rocky S-class asteroids are well understood. However, on the low-albedo C-complex asteroids, such as spacecraft targets Bennu and Ryugu, the situation is more complicated, especially due to a lack of spectral features throughout the visible-near infrared spectral region. Here we show, through a combination of observ…
Global Distribution of the Solar Wind Flux and Velocity From SOHO/SWAN During SC-23 and SC-24
Schmidt, W.; Quémerais, E.; Koutroumpa, D. +1 more
We analyze SOHO (SOlar Heliospheric Observatory)/SWAN (Solar Wind ANisotropy) hydrogen Lyman-α data collected between 1996 and 2018 to derive the solar wind latitudinal distribution over time. Full-sky interplanetary Lyman-α maps are inverted to derive the total hydrogen ionization rate latitude profiles, normalized to proton charge-exchange and p…