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 20 of 20 for “"geomagnetic storms"”.
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Automatic prediction of solar flares and super geomagnetic storms
… on space system, satellite-based services. A geomagnetic storm, a disturbance in Earth's magnetosphere, may produce many harmful effects on Earth. Solar flares and Coronal Mass Ejections (CMEs) are believed to be the major causes of geomagnetic storms. Thus, establishing a real time …
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Incoherent Scatter Radar Observations of Dynamic Ion Composition Changes at High Latitudes during Geomagnetic Storms
… = nNO+) diurnal trends, LT minimum and maximum, geomagnetic activity trends, and F region molecular ion increases due to frictional heating. Other results include rather large increases of F region molecular ion concentrations after sunrise during storms, a quantitative analysis of the crossover …
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The role of N+ in the decay of the ring current during geomagnetic storms by means of charge exchange interactions
Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2024-12-01
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Multifractal Analysis of Geomagnetically Induced Currents using Wavelet Leaders
… Meteorological Institute, which were induced by geomagnetic storms on pipelines located in Finland and recorded in 2003. Specifically, we perform a wavelet leader multifractal analysis of these current signals to generate singularity spectra, and then using the bootstrapping technique, we apply …
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Precise orbit determination and analysis from satellite altimetry and laser ranging
… the modelling of density changes associated with geomagnetic disturbances comes under scrutiny in this section. By introducing persistence modelling of a geomagnetic event and solving for certain geomagnetic parameters, a new density model is derived which performs significantly better than the …
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Quantification of the spatial structure and temporal variability of Earth's exosphere using optical tomography
… Earth's magnetic and plasma environment known as geomagnetic storms. This thesis presents several case studies of both static and time-dependent H density estimation during quiet- and storm-time conditions. This work yielded two primary findings: (i) solar radiation pressure induces Sun-Earth …
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Geomagnetically induced currents and its presence in the Eskom transmission network
… into the possible existence and occurrence of Geomagnetically Induced Currents (GICs) in the Eskom MTS. The project commenced in January 1999 and is a joint collaboration between Eskom, the University of Cape Town and EPRI. Eskom has been aware since about 1990, that occasional severe …
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UNDERSTANDING ION SPECTRAL DYNAMICS NEAR THE INNER EDGE OF THE PLASMA SHEET
… spatial distribution, and dependence on energy, geomagnetic activity, and ion species (H+, He+, and O+) are established through large-scale statistical studies of ion nose structures using measurements from the Cluster and Van Allen Probes missions. To gain physical insight into the main …
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Observations of the thermosphere using measurements from long-term Fabry-Perot interferometers
… be made during both quiet conditions and geomagnetic storms. As a compounding factor, thermospheric data have been historically lacking compared to the plentiful plasma datasets. Neutral wind and temperature data are needed to understand and validate the physics of the upper atmosphere. As …
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Effects of solar particle events on Geospace
… and the ionosphere are studied in relation to geomagnetic storms, cutoff latitude depression, substorms and polar cap absorption. The energetic proton populations of three selected SEP events from 2001 are used as 'tracers' to quantify the compression of the geomagnetic cavity during storm …
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Solar wind stream interfaces: The importance of time, longitude, and latitude separation between points of observation
… at Earth, which are known to cause recurrent geomagnetic storms.</p>
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Morphology and dynamics of storm-time ionospheric density structures
… for tracking polar cap patches during a moderate geomagnetic storm interval. For the first time, we monitor the transportation of patches with high spatial and temporal resolution across the polar cap for 1--2~h using a combination of GPS TEC, all-sky airglow imagers (ASIs), and Super Dual Auroral …
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Modeling the Energetics of the Upper Atmosphere
… times of thermospheric densities following geomagnetic storms, suggesting that an improved treatment of nitric oxide chemistry is required to resolve this issue. In order to improve our understanding of the thermospheric energy budget, we also develop the Atmospheric Chemistry and Energetics …
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PROPERTIES AND CORRELATION OF FLARES AND CORONAL MASS EJECTIONS AND THEIR POSSIBLE RELEVANCE ON THE SOUTHERN NIGHT SKY BACKGROUND : A STATISTICAL STUDY
This Thesis is devoted to a statistical study of solar phenomena (flares and coronal mass ejections) and their possible effects on the Earth. The Sun, our star, can be considered a huge laboratory where we can study the interaction of a ionized gas with magnetic fields. In particular, the solar …
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Ensemble estimation and analysis of network parameters: strengthening the GIC modelling chain
… been known to be affected by solar activity and geomagnetic storms. Geomagnetically induced currents (GICs) in these quasiantennas are just one of the effects. In modern times, society has become more and more dependent on electrical power and, as a result, power networks. These power networks …
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Satellite Drag and Sustainable Space Operations in a Dynamic Thermosphere
… per day due to unpredictable solar and geomagnetic activity. Even over short timescales, trajectory prediction is challenging because existing forecasts exhibit limited predictive skill. Although forecast errors are often non-Gaussian and heteroscedastic, operational products are …
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Identifying Ionospheric Scintillation in the South Atlantic Magnetic Anomaly using motion-affected GPS data from a ship-based receiver
… high-energy particles into the ionosphere during geomagnetic storms. Ionospheric scintillations are rapid fluctuations in the phase and amplitude of trans-ionospheric radio signals resulting from electron density variations along the ray path. As a result, spacebased navigation systems can …
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Midlatitude thermospheric wind and temperature: networked Fabry-Perot interferometer observations and radiative transfer modeling
… the midlatitude thermospheric response to the geomagnetic storm of 01-02 Oct 2013. Though the horizontal wind and temperature measurements corroborate previous observations and theory in a broad sense, the downward vertical winds measured by six independent FPIs are unreasonably large (>100 …
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An Investigation of magnetic storm effects on total electron content over South Africa for selected periods in solar cycles 23 and 24
… of the effect of mid-latitude magnetic storms on TEC over South Africa for portions of Solar Cycles 23 and 24. The MAGIC package was used to estimate TEC over South Africa during Post Solar Maximum, Solar Minimum, and Post Solar Minimum periods. It is found that TEC is largely determined …