Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 12 of 12 for “"the neutral atmosphere"”.
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Modeling the Neutral Atmosphere in Continuously Operating GNSS Networks using OPUS-Projects
<p>The Height Modernization Program, which has been designed and is being implemented by the National Geodetic Survey (NGS), is an ongoing operation focused on forming accurate, reliable heights using the Global Navigation Satellite System (GNSS) technology. The determination of GPS-derived …
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Solar activity variations of the ionospheres of Venus and Mars
Extreme ultraviolet and X-ray photons from the Sun generate a partially ionized region in the atmosphere of a planet called an ionosphere. Solar activity, including solar flares, coronal mass ejections, and changes in the ionizing irradiance affect planetary ionospheres on short and long …
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Flow/field model of a hot magnetized plasma interacting with a cold neutral atmosphere
… wind interactions with planets that possess neither an intrinsic magnetic field nor a significant ionosphere have not been well studied. We have constructed a model to simulate the interaction between a hot magnetized plasma and a planet containing only a neutral atmosphere. Examination of the …
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Atmospheric signal delay affecting GPS measurements made by space vehicles during launch, orbit and reentry
In this thesis, I present neutral atmosphere, ionosphere and total delays experienced by GPS signals traveling to space vehicles during launch, orbit and reentry. I calculate these delays for receivers at 0 km to 1700 km altitude by ray-tracing through the Global Reference Atmosphere Model (1999) …
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Incoherent Scatter Radar Observations of Dynamic Ion Composition Changes at High Latitudes during Geomagnetic Storms
… incoherent scatter radar (ISR) measurements. These methods address incoherent scatter spectra temperature-mass ambiguities by self-consistently modeling ion temperature profiles as a function of electric fields and plasma interactions with the neutral atmosphere. These two new methods improve …
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Investigation of a gravity wave ducting event in the upper mesosphere
… gravity waves (GWs) play an important role in the transport of energy and momentum throughout the Earth’s atmosphere. GW effects couple the lower regions of the atmosphere with the middle and upper regions of the atmosphere and the neutral atmosphere with the ionosphere. The effects are …
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Ionospheric Disturbances: Midlatitude Pi2 Magnetospheric ULF Pulsations and Medium Scale Traveling Ionospheric Disturbances
The ionosphere is an electrically charged atmospheric region which is coupled to the sun, the magnetosphere, and the neutral atmosphere. The ionospheric state can significantly impact technological systems, especially those which utilize radio frequency energy. By studying ionospheric disturbances, …
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Development of a Ground Based Atomic Oxygen and Vacuum Ultraviolet Radiation Simulation Apparatus
<p>The space environment possesses numerous unique and unusual attributes, creating challenges that must be considered in order to accomplish a successful space mission. Two of the detrimental aspects of the space environment include Atomic Oxygen, AO, and Ultraviolet, UV, radiation. UV radiation …
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The mid-latitude ionosphere under quiet geomagnetic conditions: propagation analysis of SuperDARN radar observations from large ionospheric perturbations
The Earth's ionosphere is a dynamic environment strongly coupled to the neutral atmosphere, magnetosphere and solar activity. In the context of this research, we restrict our interest to the mid-latitude (a.k.a., sub-auroral) ionosphere during quiet geomagnetic conditions. The Super Dual Auroral …
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Impacts of Anisotropy, Wave Heating, and Neutral Winds on High-Latitude Ionospheric Dynamics
… ion acceleration by broadband ELF waves can give the upflowing ions sufficient energy for the mirror force to propel these ions to escape into the magnetosphere (ion outflow). In order to accurately examine the connection between upflow and outflow processes, a new two dimensional, anisotropic fluid …
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Improving nanosatellite capabilities for atmospheric sounding and characterization
… vapor, and composition are important to users in the Earth science, defense, and intelligence communities. Nanosatellites (with mass < 10 kg, such as CubeSats) can support miniaturized instruments for atmospheric sounding and characterization. Nanosatellite constellations can improve spatial and …
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Development of ground and space based instrumentation for middle and upper atmospheric studies
The first objective of this research effort is to investigate the use of a high power-aperture Rayleigh lidar to measure neutral density and temperature in the upper atmosphere, into the lower thermosphere (>90 km). The scientific interest with this system is to obtain measurements of atmospheric …