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 15 of 15 for “"Quiet time"”.
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Large-scale observations of the spatial and temporal dynamics of quiet-time Sub-auroral Polarization Streams using SuperDARN HF Radars
… Previous studies have identified disturbed-time SAPS to be a geomagnetic activity dependent phenomenon, which exhibits average pre-midnight and post-midnight velocities of 1000 m/s and 400 m/s respectively. Numerous studies have reported even narrower and more intense westward plasma flows …
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Stilte, gebed en lectio divina : kreatiewe hulpmiddele in die pastorale intervensieproses na trauma
… that is researched in this study is: Silence (quiet time), prayer and lectio divina: Creative resources in the pastoral intervention process after trauma. The focus of the study is to determine to which degree aspects such as quiet time, prayer and lectio divina may be used as creative …
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Synoptic variability of a CIR-driven open-closed boundary during solar minimum
The year 2008 marked a historically quiet period of solar activity during the declining phase of solar cycle 23. Such quiet time has permitted researchers to clearly distinguish the spectral signature of a corotating interaction region's (CIR) impact on the open-closed boundary (OCB) of the …
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Analysis of Refractive Effects on Mid-Latitude SuperDARN Velocity Measurements
First time ionospheric refractive index values have been determined at mid latitudes using frequency switched SuperDARN plasma convection velocity estimates. Previous works have found a disparity between high latitude SuperDARN plasma convection velocities and those made by other devices. It was …
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Ring current -atmosphere interactions model with stormtime magnetic field
… is presented in this thesis. The recent stormtime empirical model T04s and the IGRF model are used to represent the Earth's external and internal magnetic fields respectively. Particle drifts, losses due to charge exchange with geocoronal hydrogen and atmospheric losses are included in the …
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Incoherent Scatter Radar Observations of Dynamic Ion Composition Changes at High Latitudes during Geomagnetic Storms
… for data collected with short integration times (2-10 minutes). The improved models incorporate the effects of variable scale height, altitude dependent neutral winds (taken from the horizontal wind model 2007), and Coulomb collisions, while the fitting schemes simultaneously determine both …
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High-latitude electron density observations from the IMAGE radio plasma imager
… over a 60-minute interval. During steady quiet-time solar wind and interplanetary magnetic field conditions, the cusp is shown to be stable in both position and density structure with only slight variations in both. Peak electron densities within the cusp during this time are found to be …
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Observations of the thermosphere using measurements from long-term Fabry-Perot interferometers
… of ionospheric phenomena 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 …
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Meanings of 'the Outdoors': Shaping outdoor education in Aotearoa New Zealand
… activities, spontaneous learning moments, and quiet time into many of their sessions. In so doing, they ensured experiences for their students were holistic, meaningful, and engaging, as well as promoting a respectful relationship with 'the outdoors'. Some of these practices were constrained at …
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Driving Influences of Ionospheric Electrodynamics at Mid- and High-Latitudes
… can have dual flow responses with different lag times to strong dynamic IMF conditions that involve IMF By rotation. We proposed a dual reconnection scenario, one poleward of the cusp and the other at the magnetopause nose, to explain the observed flow behavior. In Chapters 3 and 4, we …
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SuperDARN Data Simulation, Processing, Access, and Use in Analysis of Mid-latitude Convection
… SuperDARN chain has revealed that nighttime, quiet-time plasma irregularities with low Doppler velocity and spectral width are a very common (> 50% of nights) occurrence. Following on previous work, we have conducted a study of nighttime midlatitude convection using SuperDARN data. …
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Study of waves observed in the equatorial ionospheric valley region using Jicamarca ISR and VIPIR ionosonde
… waves playing a role in modulating the space-time structure of the 150-km echoes. Fluctuations with periods from 5 to 15 minutes are observed in VIPIR ionograms as well as in the layers found in the 50 MHz radar range-time-intensity (RTI) plots. The quiet-time stratified electron density …
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The mid-latitude ionosphere under quiet geomagnetic conditions: propagation analysis of SuperDARN radar observations from large ionospheric perturbations
… (a.k.a., sub-auroral) ionosphere during quiet geomagnetic conditions. The Super Dual Auroral Radar Network (SuperDARN) is composed of more than 30 low-power High Frequency (HF, from 8-18 MHz) Doppler radars covering the sub-auroral, auroral and polar ionosphere in both hemispheres. …
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Midlatitude D Region Variations Measured from Broadband Radio Atmospherics
… sferic spectra from using a finite difference time domain (FDTD) code.</p><p>In order to understand the time scales, magnitudes and sources for the midlatitude nighttime <italic>D</italic> region variations, we analyzed the sferic data of July and August 2005, and extracted both the height and …
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The Mid-Latitude Ionosphere: Modeling and Analysis of Plasma Wave Irregularities and the Potential Impact on GPS Signals
… for the growth of these irregularities, a time series for the growth rate of both TGI and GDI is developed. The time series is computed for both perpendicular and meridional density and temperature gradients. The growth rate comparison shows that the TGI is the most likely generation …