Sökning: "geomagnetic activity"

Visar resultat 16 - 20 av 25 avhandlingar innehållade orden geomagnetic activity.

  1. 16. Radar Signatures of Auroral Plasma Instability

    Författare :Nicola Schlatter; Nickolay Ivchenko; Anja Stromme; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Ionosphere; Particle Precipitation; Instability; Plasma Turbulence; Fysik; Physics;

    Sammanfattning : Incoherent scatter radars are powerful ground based instruments for ionospheric measurements. By analysis of the Doppler shifted backscatter spectrum, containing the signature of electrostatic plasma waves, plasma bulk properties are estimated. LÄS MER

  3. 17. Satellite observations of auroral acceleration processes

    Författare :Lars Eliasson; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Aurora; particle acceleration; space plasma; magnetosphere; ionosphere; polar cap; satellite observations;

    Sammanfattning : Measurements with satellite and sounding rocket borne instruments contain important information on remote and local processes in regions containing matter in the plasma state. The characteristic features of the particle distributions can be used to explain the morphology and dynamics of the different plasma populations. LÄS MER

  4. 18. Long-term observations of polar mesosphere summer echoes using the ESRAD MST radar

    Författare :Maria Smirnova; Patrick Joseph Espy; Luleå tekniska universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Rymdteknik; Space Technology;

    Sammanfattning : Polar Mesosphere Summer Echoes (PMSE) are strong radar echoes observed from altitudes of 80-90 km in polar regions, during summer time. PMSE are closely related to the fascinating atmospheric phenomenon known as noctilucent clouds (NLC). LÄS MER

  5. 19. Global Magnetospheric Plasma Convection

    Författare :Stefan Eriksson; KTH; []
    Nyckelord :Geophysics; satellite measurements; electric fields; magnetosphere; magnetic reconnection;

    Sammanfattning : This thesis deals with the global aspects of plasmaconvection in the magnetosphere as measured by the low-altitudepolar orbiting Astrid-2 and FAST satellites. The major focus ison the electric field measurements, but they are alsocomplemented by magnetic field, ion and electron particle data,which is fundamental for the understanding of theelectrodynamics of the high-latitude auroral ovals and polarcap, which are the regions analysed here. LÄS MER

  7. 20. A multimethod approach to dating Quaternary sediments from the Arctic Ocean

    Författare :Gabriel West; Matthew O'Regan; Darrell Kaufman; Helena Alexanderson; Guillaume St-Onge; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Arctic Ocean; Amino Acid Geochronology; Optically Stimulated Luminescence Dating; Palaeomagnetism; maringeologi; Marine Geology;

    Sammanfattning : The marine sedimentary environment in the polar regions is different from the rest of the world’s oceans, as it is greatly influenced by the cryosphere. In the Arctic, sea ice and icebergs can transport vast amounts of sediments, delivered by extensive fluvial systems from the surrounding continents, which have been shaped by the waxing and waning of large terrestrial ice sheets during the Quaternary period. LÄS MER