Stephen W. Bougher

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[1] Warming of the martian lower thermosphere (100–130 km) at north polar latitudes near the perihelion/winter solstice (Ls = 270) was recently observed. No analogous warming has been observed within the south polar thermosphere during its aphelion/winter season (Ls 90). Detailed global model simulations are required to investigate the physical processes(More)
[1] Dayglow ultraviolet emissions of the CO Cameron bands and the CO2 + doublet in the Martian atmosphere have been observed with the Spectroscopy for Investigation of Characteristics of the Atmosphere of Mars on board the Mars Express spacecraft. A large amount of limb profiles has been obtained which makes it possible to analyze variability of the(More)
[1] Martian electron density profiles provided by the Mars Global Surveyor (MGS) Radio Science (RS) experiment over the 95–200 km altitude range indicate wthat the height of the electron peak and the longitudinal structure of the peak height are sensitive indicators of the physical state of the Mars lower and upper atmospheres. The present analysis is(More)
Mars Global Surveyor accelerometer observations of the martian upper atmosphere revealed large variations in density with longitude during northern hemisphere spring at altitudes of 130–160 km, all latitudes, and mid-afternoon local solar times (LSTs). This zonal structure is due to tides from the surface. The zonal structure is stable on timescales of(More)
We apply improved kinetic modeling of electron transport in the martian thermosphere to fit pitch angle distributions measured by the Mars Global Surveyor (MGS) Magnetometer/Electron Reflectometer (MAG/ER), together with appropriate filtering, binning, averaging and error correction techniques, to create the most reliable ER global map to date of crustal(More)
[1] The response of the Mars dayside exospheric temperatures to short and long term solar flux changes was recently established. Characterization of the relative importance of various thermospheric heating and cooling mechanisms for maintaining these Mars exospheric temperatures requires the systematic application of modern global dynamical models that(More)
[1] We present a new technique for inferring neutral densities in the Martian upper atmosphere from atmospheric absorption of magnetically reflected solar wind electrons. Using electron loss cone measurements from the Magnetometer/Electron Reflectometer (MAG/ER) experiment on board Mars Global Surveyor (MGS), we derive upper thermospheric ( 160–230 km(More)
[1] The global dynamics of the flow of energetic particles through the Martian upper atmosphere is studied for different cases reflecting variations in solar cycle, seasons, and epochs over history. In this study, the combination of the new 3-D Direct Simulation Monte Carlo kinetic model and the modern 3-D Mars Thermosphere General Circulation Model is(More)
The Mars Atmosphere and Volatile EvolutioN (MAVEN) Neutral Gas and Ion Mass Spectrometer (NGIMS) provides sensitive detections of neutral gas and ambient ion composition. NGIMS measurements of nine atomic and molecular neutral species, and their variation with altitude, latitude, and solar zenith angle are reported over several months of operation of the(More)
[1] We employ a newly developed Navier‐Stokes model, the Titan Global Ionosphere‐Thermosphere Model (T‐GITM) to address the one dimensional (1‐D) coupled composition, dynamics, and energetics of Titan’s upper atmosphere. Our main goals are to delineate the details of this new theoretical tool and to present benchmark calibration simulations compared against(More)