Now showing items 1-20 of 31

    • Air temperature at 90 km altitude in the Artic obtained using meteor radar : validation, characterization and climate change. 

      Kluken, Lars Grytbakk (Master thesis; Mastergradsoppgave, 2011-09-30)
      Temperatures at 90 km altitude above Ramfjordmoen (69°N, 19°E) have been obtained with the Nippon/Norwegian Tromsø Meteor Radar. The temperatures have been derived from meteor radar decay rates using two techniques: the pressure based and the temperature gradient based methods. The results have been compared to the Microwave Limb Sounder (MLS) instrument on board the Aura spacecraft. It was found ...
    • Analysis of the potential of the Ku-band Gamma Portable Radar Interferometer for sea ice information extraction. 

      Asbjørnslett, Andreas Hansen (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 ...
    • Angular dependence of wide altitude ion line enhancements (WAILEs) during ionospheric heating at the EISCAT Tromsø Facility 

      Bazilchuk, Zoë Strimbeck (Master thesis; Mastergradsoppgave, 2019-06-01)
      This thesis presents the first sub-radar beam resolution determination of the angular width of wide altitude ion line enhancements (WAILEs), found to be 0.5 degrees around magnetic zenith, observed during a HF radio wave heating experiment at the EISCAT Tromsø Heating facility on 27 November 2014. The results of ray tracing simulations are detailed. The simulations are based on the hypothesis that ...
    • Arctic Cirrus Clouds: A Comparison of Properties Derived from Measurements by Ground-Based and Spaceborne Lidar Systems 

      Hanssen, Ingrid Margrethe Vestnes (Master thesis; Mastergradsoppgave, 2015-12-15)
      The purpose of this thesis is to investigate Arctic cirrus clouds. In this work, data from the ground-based lidar system at ALOMAR, Andøya Space Center. and the spaceborne lidar onboard the CALIPSO satellite is used. Cirrus clouds are an important factor in modeling climate changes, which is one of the major research fields of this time. Most of the cirrus cloud research concentrates on investigating ...
    • Arctic Thin Sea Ice Thickness Regression Models for Sentinel-2 

      Skogvold, Øystein Fredriksen (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) ...
    • Automatic Detection of Naturally Enhanced Ion-Acoustic Lines in EISCAT data 

      Mikalsen, Kristian (Master thesis; Mastergradsoppgave, 2016-06-01)
      Naturally Enhanced Ion-Acoustic Lines (Neials) are small-scaled and short-lived phenomena in the ionosphere, which is widely researched internationally. At present, the search for Neials is a tedious task that has to be done through visual inspection. This is often a time-consuming process and limits the research on Neials. By automating the means of locating the Neials, the access to them will be ...
    • Beam and plasma properties downstream from positively biased source chamber 

      Osnes, Sindre (Master thesis; Mastergradsoppgave, 2017-06-06)
      We study the effect of changing the separation grid bias in a double plasma device from -50 V to the same bias as the anode in the source chamber, 115 V on the plasma and beam parameters downstream in the target chamber. Two different probes were used to analyze the downstream plasma. We used an RFEA-probe to obtain information about the ions, such as the ion energy distribution and we constructed ...
    • Characterization of a magnetized plasma in cylindrical geometry 

      Tribulato, Giulio (Master thesis; Mastergradsoppgave, 2007-06)
      Njord is a novel plasma device in which a low-temperature plasma is produced by RF waves inductively coupled into a cylindrical, magnetized vacuum. The main part of this project is to carry out an experimental characterization of the plasma in this device. The plasma expansion and acceleration of the source plasma into the main chamber will be of specific interest. The ultimate aim will then be to ...
    • Charging Effects and Detection of Mesospheric Dust with the Instrument SPID on the G-Chaser Rocket 

      Gunnarsdottir, Tinna (Master thesis; Mastergradsoppgave, 2019-06-01)
      Smoke Particle Impact Detector (SPID) is a faraday cup impact probe designed and built by the University of Tromso (UIT). Its main purpose is to measure nanometer sized smoke particles (in-situ) in the atmosphere, and to do that it needs to be launched on a sounding rocket. Its design is an open faraday cup with grids to shield out ambient plasma and a larger slanted impact grid to measure the ...
    • A Comparison of Naturally Enhanced Ion Acoustic Lines and Auroral Spectral Line Emissions 

      Hansen, Rikke Hedelund (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 ...
    • Cross-Phase Based Multi-Camera Video Synchronization Calibration with Sub Frame Rate Accuracy 

      Sivasothy, Pavithiran (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 ...
    • Design and Implementation of a Software Defined Ionosonde. A contribution to the development of distributed arrays of small instruments 

      Floer, Markus (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 ...
    • Determining optical-flow for turbulent motions in the aurora borealis 

      Jakobsen, Kim André (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 ...
    • Estimating thermospheric neutral densities using ISR-observations during active HF-radio wave ionospheric heating experiment 

      Pedersen, Marcus Nicolai (Master thesis; Mastergradsoppgave, 2017-12-15)
      In this study we present a method to estimate neutral thermospheric densities using ISR-observations following a sequence of high-frequency radio wave ionospheric heating modi cations in the vicinity of the ionosphere peak density altitude (hmF2), and the results from two different days of observations with low geomagnetic activity levels (AP<4) that are compared to the MSIS model. Slight ...
    • Influence of Meteoric Aerosol particles on the Charge Balance in the Upper Mesosphere During ECOMA 2010 

      Svendsen, Åse (Master thesis; Mastergradsoppgave, 2011-12-15)
      This work is focused on the three sounding rocket launches during the ECOMA Geminids campaign in December 2010: One before the Geminids meteor shower, one at its peak and one some days after the peak. In this work, the main emphasis is on analyzing the results from electron and ion probes on the rockets, obtaining electron and ion density profiles, and comparing them with the measurements of meteoric ...
    • Installation and characterization of an electron bombardment ion source for a Space Simulation Chamber (SSC) 

      Dyrland, Karianne (Master thesis; Mastergradsoppgave, 2016-12-15)
      The primary focus of this thesis is the installation and characterization of an electron bombardment ion source for a Space Simulation Chamber (SSC). The goal is that the chamber can be used to test satellite and sounding rocket instrumentation, thus be capable of producing ionospheric plasma conditions, along with an ion beam that can simulate the velocity of a rocket or satellite relative to the ...
    • Interplanetary dust fluxes observed with Parker Solar Probe 

      Henriksen, Emil Gorseth (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 ...
    • An Investigation of Magnetic Field Disturbances on the Ground and in the Mesosphere 

      Eriksen, Nina Kristine (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 ...
    • An investigation of the spatial and temporal distribution of kinetic energy in the mesosphere. The high latitude mesosphere 

      Nordaunet, Ole Kalstad (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 ...
    • A model for IS spectra for magnetized plasma with arbitrary isotropic velocity distributions 

      Enger, Eirik Rolland (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 ...