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norskMastergradsoppgaver i teknologi - romfysikk
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A new Method for Estimating 3-Dimensional Ionospheric Currents from Ground-Based Magnetometers
(Mastergradsoppgave; Master thesis, 2022-07-17)The ionosphere is a region of the upper atmosphere where a significant rate of photo-ionisation from solar ultraviolet radiation cause an increased plasma density. In this region a system of electrical currents flow, driven by electric fields generated by fluctuating dynamics within the Earths magnetosphere. These fluctuating dynamics are caused by interactions between the magnetosphere and the solar ... -
Interstellar Dust in the Inner Heliosphere and Impact Detection Capabilities with ESA's Solar Orbiter Spacecraft
(Master thesis; Mastergradsoppgave, 2022-05-31)ESA’s Solar Orbiter spacecraft provides a new opportunity to investigate the inner heliosphere close to sun, by taking measurements with state-of-the-art instruments it will help uncover the mysteries of the Sun. Solar Orbiter is planned for a 7 year mission, reaching as close as 0.28 AU to the sun. Using a process called impact ionization, dust fluxes can be measured during the mission. Some ... -
Polar Mesospheric Winter Echoes - an analysis of selected cases
(Mastergradsoppgave; Master thesis, 2022-05-31)Polar Mesospheric Winter Echoes (PMWE) are strong coherent radar echoes, from the upper mesosphere at 55-85 km that are observed typically from end of August until beginning of May. Some models to explain PMWE formation suggest that they form because of turbulence in the atmosphere. Other models suggest that the PMWEs form like summer polar mesospheric echoes (PMSE) where charged dust particles ... -
Frequency Dependence of Ionospheric Electron Heating Around the Third Double Resonance
(Mastergradsoppgave; Master thesis, 2022-05-31)The partly ionized ionosphere responds differently to high power, high frequency radio waves based on the wave frequency, the wave power, the wave polarization, and the propagation angle relative to the magnetic field. Ionospheric modification experiments are conducted to investigate the responses and their dependencies, setting experimental constraints on the contributions from non-resonant collisional ... -
Disambiguation of range-Doppler radar measurements
(Mastergradsoppgave; Master thesis, 2022-05-31)Observing the Moon by a monostatic synthetic-aperture radar system has the inherent problem that any given combination of range and Doppler shift in a measurement will map to two different regions on the lunar surface. This ambiguity has previously been avoided using an interferometric radar configuration or selective illumination. The objective of this thesis was to write and validate a method for ... -
Design and implementation of an oblique ionosonde receiver. For studies of spatial and temporal ionospheric structures
(Mastergradsoppgave; Master thesis, 2022-05-27)The study of the ionosphere has been of central interest since its discovery in the early 20th century. In later decades there has been an increasing appreciation and need for understanding the spatial and temporal structure of the ionosphere and how the structure is affected by various processes in the atmosphere. An important process in this context is that of atmospheric gravity waves ... -
The influence of mass loss on the dynamics of dust near the Sun
(Mastergradsoppgave; Master thesis, 2021-12-28)The Parker Solar Probe (PSP) mission by NASA and the Solar Orbiter (SolO) mission by ESA are two recently launched missions that measure dust in the inner solar system. The dust is produced by fragmentation of meteoroids, which are large fragments of the asteroids and comets. The dust particles are small enough that their motion is affected by the radiation pressure force from the Sun. Dust fragments ... -
Radar observations of space debris in polar orbits 2018–2021. A study on the evolution of the Microsat-R fragments
(Master thesis; Mastergradsoppgave, 2021-07-02)Orbits are an invaluable resource for the global community. However, space pollution is becoming more pronounced as the accumulation of debris continues. Deliberate collisions are a relevant source contributing to this development. When Microsat-R was destroyed with a missile in 2019, it ejected numerous fragments into orbit. Based on observations made with EISCAT UHF, this thesis will investigate ... -
On Trapped Particle Dynamics in Rotating Frames
(Mastergradsoppgave; Master thesis, 2021-07-01)The rapid rotation of Jupiter and Saturn, combined with internal source of plasma provided by their moons Io and Enceladus respectively, creates a magnetodisk structure of the planetary magnetic field. The magnetodisk looks like a stretched dipole magnetic field in the equatorial region, where centrifugal force is largest. The centrifugal force, originating in the rotating frame, is known to have ... -
A model for IS spectra for magnetized plasma with arbitrary isotropic velocity distributions
(Mastergradsoppgave; Master thesis, 2020-06-27)The plasma line in the incoherent scatter spectrum is known to provide information about the state of the ionosphere. However, it is weak in signal strength and therefore difficult to measure reliably and consistently. When high-energetic electrons (suprathermal electrons) are present in the ionosphere the plasma line echo power is enhanced and detectable by more radars. Recent measurements made by ... -
Design and Implementation of a Software Defined Ionosonde. A contribution to the development of distributed arrays of small instruments
(Master thesis; Mastergradsoppgave, 2020-06-29)In order to make advances in studies of mesoscale ionospheric phenomena, a new type of ionosonde is needed. This ionosonde should be relatively inexpensive and small form factor. It should also be well suited for operation in a network of transmit and receiver sites that are operated cooperatively in order to measure vertical and oblique paths between multiple transmitters and receivers in the ... -
Predicting the Auroral Oval Boundaries by Means of Polar Operational Environmental Satellite Particle Precipitation Data
(Master thesis; Mastergradsoppgave, 2020-06-29)New empirical Kp-based models for the equatorward and poleward boundaries of the auroral oval in the Northern and Southern Hemispheres were developed, with the purpose of reviewing the auroral ovals predicted by well-established Feldstein auroral oval model. The new models were derived from particle and energy flux measurements from six low-altitude (800-900 km) POES/MetOp satellites. The equatorward ... -
Interplanetary dust fluxes observed with Parker Solar Probe
(Master thesis; Mastergradsoppgave, 2020-06-29)The mission Parker Solar Probe (PSP) provides a new opportunity to make in-situ measurements of dust impacts closer to the Sun than ever before, eventually going as close as ∼ 10 solar radii or ∼ 0.05 AU. PSP can measure dust impacts from monopole measurements of the spacecraft’s electric potential to one of its antennas using its FIELDS instrument. In this work impact rates data is compared ... -
Cross-Phase Based Multi-Camera Video Synchronization Calibration with Sub Frame Rate Accuracy
(Master thesis; Mastergradsoppgave, 2020-06-29)In auroral research, it is necessary to accurately measure the time-shift differences between varying light sources. Such measurements can be carried out using two or more digital cameras, or between different regions of an image obtained using a single camera. An example of this is measurements of the time-shifts between prompt auroral emissions originating from different altitude regions during ... -
An investigation of the spatial and temporal distribution of kinetic energy in the mesosphere. The high latitude mesosphere
(Master thesis; Mastergradsoppgave, 2020-06-29)The mesosphere is perhaps the least explored region in the atmosphere with very few methods of observing. This thesis will primarily be exploring a new technique for measuring the distribution of kinetic energy in the mesosphere across a wide range of spatial and temporal scales. The method being used relies on correlation functions between pairs of meteor measurements. These measurements are made ... -
Analysis of the potential of the Ku-band Gamma Portable Radar Interferometer for sea ice information extraction.
(Master thesis; Mastergradsoppgave, 2020-06-29)Radar remote sensing is a key technology for monitoring sea ice. In this regard, passive microwave and Synthetic Aperture Radars (SARs) are the most important sensor types. This technology has been used for sea ice applications for four decades, but there are still many uncertainties related to sea ice monitoring by SAR. Some of these may be solved by multi-sensor observations, in which case other ... -
Determining optical-flow for turbulent motions in the aurora borealis
(Master thesis; Mastergradsoppgave, 2020-06-28)In dynamic aurora there are structures that shows shear-flow and rotations. These flows have a locally varying vorticity-field, which can be observed in small scale aurora. Vorticity in plasma-flows have a direct relation to field-aligned currents. An effective method to determine these flows would be a great tool in research on magnetosphere-ionosphere coupling and auroral physics. With the current ... -
An Investigation of Magnetic Field Disturbances on the Ground and in the Mesosphere
(Master thesis; Mastergradsoppgave, 2019-05-31)Geomagnetic field models can be a useful tool for when and where there are no measurements available, or access is limited, because of a highly spatially uneven magnetometer network around the globe. The same can be said for altitudes above the ground, but below the ionospheric current layer, where there exist no in situ measurements at the point of writing. Modelled geomagnetic disturbances have ... -
A Comparison of Naturally Enhanced Ion Acoustic Lines and Auroral Spectral Line Emissions
(Master thesis; Mastergradsoppgave, 2019-05-31)In this thesis, we present Naturally Enhanced Ion Acoustic Lines (NEIALs) observed with the EISCAT Svalbard Radar and a comparison with auroral emissions lines measured with a Meridian Scanning Photometer. NEIALs are short-lived events noticeable in the incoherent scatter spectra as an enhancement in one or both shoulders. It has been assumed that NEIALs are associated with an active red emission ... -
Arctic Thin Sea Ice Thickness Regression Models for Sentinel-2
(Master thesis; Mastergradsoppgave, 2019-05-31)Sea ice thickness is an important parameter for modelling the sea ice mass balance, momentum and gas exchanges, and global energy budget. The interest of studies into thin sea ice has increased as trends in recent years show a increasing abundance in thin first year ice. Existing thin sea ice thickness products operate at resolutions down to 750 meters. Very high resolution (less than 100 meters) ...
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