Search Publications
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…
Electron Scale Measurements of Antidipolarization Front
Liu, Chengming; Cao, Jinbin; Fu, Huishan +3 more
Antidipolarization fronts (ADFs), usually formed at the leading edge of the tailward reconnection jets in the Earth's magnetotail, are characterized by sharp enhancements of southward magnetic field (negative Bz). The fine structures at electron scale of the ADFs have not been studied so far, due to instrumental limitations and large se…
Statistical Investigation of the Frequency Dependence of the Chorus Source Mechanism of Plasmaspheric Hiss
Shen, Xiao-Chen; Meredith, Nigel P.; Horne, Richard B. +2 more
We use data from eight satellites to statistically examine the role of chorus as a potential source of plasmaspheric hiss. We find that the strong equatorial (|λm| < 6°) chorus wave power in the frequency range 50 < f < 200 Hz does not extend to high latitudes in any magnetic local time sector and is unlikely to be the source o…
Intense dB/dt Variations Driven by Near Earth Bursty Bulk Flows (BBFs): A Case Study
Dunlop, Malcolm W.; Wei, Dong; Yang, Junying +3 more
During geomagnetically disturbed times the surface geomagnetic field often changes abruptly, producing geomagnetically induced currents (GICs) in a number of ground based systems. There are, however, few studies reporting GIC effects which are driven directly by bursty bulk flows (BBFs) in the inner magnetosphere. In this study, we investigate the…
Annual Appearance of Hydrogen Chloride on Mars and a Striking Similarity With the Water Vapor Vertical Distribution Observed by TGO/NOMAD
Aoki, S.; Vandaele, A. C.; Daerden, F. +23 more
Hydrogen chloride (HCl) was recently discovered in the atmosphere of Mars by two spectrometers onboard the ExoMars Trace Gas Orbiter. The reported detection made in Martian Year 34 was transient, present several months after the global dust storm during the southern summer season. Here, we present the full data set of vertically resolved HCl detec…
Periodic Bedrock Ridges at the ExoMars 2022 Landing Site: Evidence for a Changing Wind Regime
Pajola, M.; Tirsch, D.; Silvestro, S. +11 more
Wind formed features are abundant in Oxia Planum (Mars), the landing site of the 2022 ExoMars mission, which shows geological evidence for a past wet environment. Studies of aeolian bedforms at the landing site were focused on assessing the risk for rover trafficability, however their potential in recording climatic fluctuations has not been explo…