Sökning: "rymdfysik"

Visar resultat 11 - 15 av 240 avhandlingar innehållade ordet rymdfysik.

  1. 11. Drift-Type Waves in Rotating Tokamak Plasma

    Författare :Elina Asp; Vladimir Pavlenko; Hans Nordman; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Space and plasma physics; fusion; plasma; tokamak; rotation; drift; ship; ITG; TE; Landau; Te Ti; hot-electron; confinement; stiffness; Weiland; Rymd- och plasmafysik; Space physics; Rymdfysik; Space and Plasma Physics; rymd- och plasmafysik;

    Sammanfattning : The concept of energy production through the fusion of two light nuclei has been studied since the 1950’s. One of the major problems that fusion scientists have encountered is the confinement of the hot ionised gas, i.e. the plasma, in which the fusion process takes place. LÄS MER

  3. 12. Cluster Observations and Theoretical Explanations of Broadband Waves in the Auroral Region

    Författare :Marie Backrud; Jan-Erik Wahlund; Mats André; David Knudsen; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Space and plasma physics; ion acoustic waves; auroral region; anomalous resistivity; Cluster; Rymd- och plasmafysik; Space physics; Rymdfysik;

    Sammanfattning : Broadband extremely low-frequency wave emissions below the ion plasma frequency have been observed by a number of spacecraft and rockets on auroral field lines. The importance of these broadband emissions for transverse ion heating and electron acceleration in the auroral regions is now reasonably well established. LÄS MER

  4. 13. Dissipation at the Earth's Quasi-Parallel Bow Shock

    Författare :Rico Behlke; Mats André; Harald Kucharek; Andris Vaivads; Manfred Scholer; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Space and plasma physics; collisionless shocks; wave-particle interactions; nonlinear phenomena; cross-shock potential; Cluster spacecraft; Rymd- och plasmafysik; Space physics; Rymdfysik;

    Sammanfattning : The Earth's bow shock is a boundary where the solar wind becomes decelerated from supersonic to subsonic speed before being deflected around the Earth. This thesis presents measurements by the Cluster spacecraft upstream and at the Earth's quasi-parallel bow shock where the angle between the upstream magnetic field and the bow shock normal is less than 45 degrees. LÄS MER

  5. 14. Interaction between Electromagnetic Waves and Localized Plasma Oscillations

    Författare :Jan-Ove Hall; Thomas Leyser; Jan Trulsen; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Space and plasma physics; space physics; plasma physics; radio waves; ionospheric modification; density depleations; field-aligned irregularities; lower hybrid solitary structures; lower hybrid cavities; Z mode waves; magnetosonic waves; scattering; mode conversion; Rymd- och plasmafysik; Space physics; Rymdfysik;

    Sammanfattning : This thesis treats interaction between electromagnetic waves and localized plasma oscillations. Two specific physical systems are considered, namely artificially excited magnetic field-aligned irregularities (striations) and naturally excited lower hybrid solitary structures (LHSS). LÄS MER

  7. 15. Theory and Applications of Tri-Axial Electromagnetic Field Measurements

    Författare :Roger Karlsson; Bo Thid'e; Tobia Carozzi; Gudmund Wannberg; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Space and plasma physics; polarisation; polarization; Stokes parameters; antenna; radio waves; whistler wave; SEE; direction-finding; statistics; Poynting theorem; Rymd- och plasmafysik; Space physics; Rymdfysik;

    Sammanfattning : Polarisation, which was first studied in optics, is a fundamental property of all electromagnetic fields. A convenient way to describe the polarisation of two dimensional electromagnetic fields is given by the Stokes parameters. This thesis deals with different aspects of wave polarisation and electromagnetic field measurements. LÄS MER