Search Publications
In Situ Observation of a Magnetopause Indentation that Is Correspondent to Throat Aurora and Is Caused by Magnetopause Reconnection
Shi, Run; Li, Bin; Zhou, Su +6 more
Throat auroras have been suggested to correspond to magnetopause indentations, but how such indentations can be generated is an open question. Using coordinated magnetopause in situ and two-dimensional auroral imaging observations, we showed that a transient magnetopause crossing observed by Time History of Events and Macroscale Interactions durin…
Geologic Context of the Bright MARSIS Reflectors in Ultimi Scopuli, South Polar Layered Deposits, Mars
Landis, M. E.; Whitten, J. L.
Radar-bright basal reflectors have been detected below the South Polar Layered Deposits (SPLD), using Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) data and have an exciting but controversial interpretation: liquid water from subglacial lakes. We mapped the surface of the SPLD immediately above and surrounding the putative la…
MAVEN Proton Observations Near the Martian Moon Phobos: Does Phobos Backscatter Solar Wind Protons?
André, N.; Halekas, J. S.; Fowler, C. M. +7 more
ESA's Mars Express (MEX) may have observed twice solar wind protons backscattered by Phobos. However, these detections remain uncertain and call for an independent confirmation. Here, we analyze the proton measurements collected by the Suprathermal And Thermal Ion Composition experiment onboard NASA's Mars Atmosphere and Volatile EvolutioN mission…
Observations of Modulation of Ion Flux in the Coma of Comet 67P/Churyumov-Gerasimenko
Altwegg, K.; Nilsson, H.; Goldstein, R. +4 more
On 6-8 June 2015, the Ion and Electron Sensor on board Rosetta observed keV-range water-group pickup ions arriving from the solar direction. Based on magnetic field intensification and variations, the appearance of the ions was likely to have been caused by a coronal mass ejection. During the 3-day period when Rosetta was 200 km from the comet, pe…
Current Sheet Thinning in the Wake of a Bubble Injection
Nakamura, Rumi; Yang, Jian; Cui, Jun +3 more
A crucial property of the substorm growth phase is the current sheet thinning, which is often attributed to adiabatic convection. Injecting low-entropy bubbles reduce pressure-balance inconsistencies and restore current sheet thickness to its initial value. Recent observations from Cluster and MMS showed additional thinning of the current sheet in…
Evidence of Small Scale Plasma Irregularity Effects on Whistler Mode Chorus Propagation
Agapitov, Oleksiy; Hosseini, Poorya; Harid, Vijay +1 more
The impact of randomly distributed field aligned density irregularities on whistler mode wave propagation is investigated using full wave simulations and multipoint spacecraft observations. The irregularities are modeled as randomized density perturbations between 1% and 10% of the nominal background density value with scales of ∼10-60 km transver…
Revealing a High Water Abundance in the Upper Mesosphere of Mars With ACS Onboard TGO
Montmessin, Franck; Belyaev, Denis A.; Fedorova, Anna A. +7 more
We present the first water vapor profiles encompassing the upper mesosphere of Mars, 100-120 km, far exceeding the maximum altitudes where remote sensing has been able to observe water to date. Our results are based on solar occultation measurements by Atmospheric Chemistry Suite (ACS) onboard the ExoMars Trace Gas Orbiter (TGO). The observed wave…
Strong MARSIS Radar Reflections From the Base of Martian South Polar Cap May Be Due to Conductive Ice or Minerals
Putzig, N. E.; Bierson, C. J.; Tulaczyk, S. +1 more
Recent results from the Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) instrument have been interpreted as evidence of subsurface brine pooled beneath 1.3 km-thick South Polar Layered Deposit (SPLD). This interpretation is based on the assumption that the regionally high strength of MARSIS radar reflections from the base of th…
A Solid Interpretation of Bright Radar Reflectors Under the Mars South Polar Ice
Smith, I. B.; Horgan, B. H. N.; Whitten, J. L. +4 more
Bright radar reflections observed beneath the south polar layered deposits (SPLD) by the Mars Advanced Radar for Subsurface and Ionosphere Sounding instrument were interpreted to represent liquid water, but the required amounts of salt and heat to form and maintain liquids in this location are implausible given what is known about Mars. Here, we p…
A Stable H2O Atmosphere on Europa's Trailing Hemisphere From HST Images
Roth, Lorenz
Previous studies of the global intensities of the oxygen emissions at 1,356 Å and 1,304 Å revealed molecular oxygen (O2) in Europa's atmosphere. Here we investigate the relative changes of the two oxygen emissions when Europa emerges from eclipse as well as the radial profiles of the relative emissions across the sunlit disk in Hubble S…