Sökning: "Rymdfysik"

Visar resultat 1 - 5 av 161 avhandlingar innehållade ordet Rymdfysik.

  1. 1. Alfvén Waves and Energy Transformation in Space Plasmas

    Författare :Yuri Khotyaintsev; Kalevi Mursula; Uppsala universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; Space and plasma physics; Alfvén waves; particle acceleration; ionosphere; magnetopause; magnetic reconnection; Rymd- och plasmafysik; Space physics; Rymdfysik; Space Physics; rymdfysik;

    Sammanfattning : This thesis is focused on the role of Alfvén waves in the energy transformation and transport in the magnetosphere. Different aspects of Alfvén wave generation, propagation and dissipation are considered. The study involves analysis of experimental data from the Freja, Polar and Cluster spacecraft, as well as theoretical development. LÄS MER

  2. 2. The Polar Cusp and its Ionospheric footprint : Dynamics and Transients

    Författare :Frédéric Pitout; Ryoichi Fujii; Uppsala universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; Space and plasma physics; Solar wind - magnetosphere - ionosphère interactions; polar ionosphere; Rymd- och plasmafysik; Space physics; Rymdfysik; Space Physics; rymdfysik;

    Sammanfattning : The magnetopause, the boundary layer between the solar wind and the Earth’s magnetosphere, is not closed as we have long thought. Transfers of energy, particles and momentum from the solar wind to the magnetosphere actually take place. LÄS MER

  3. 3. The Auroral Large Imaging System : design, operation and scientific results

    Författare :Urban Brändström; Umeå universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; Space and plasma physics; Aurora; Artificial airglow; HF-pump enhanced airglow; Multistation measurements; Polar Stratospheric clouds; Radio-Induced optical emissions; Spectroscopic imaging observations; Tomography; Rymd- och plasmafysik; Space physics; Rymdfysik; rymdfysik; Space Physics;

    Sammanfattning : The Auroral Large Imaging System (ALIS) was proposed in 1989 by Åke Steen as a joint Scandinavian ground-based nework of automated auroral imaging stations. The primary scientic objective was in the field of auroral physics, but it was soon realised that ALIS could be used in other fields, for example, studies of Polar Stratospheric Clouds (PSC), meteors, as well as other atmospheric phenomena. LÄS MER

  4. 4. The importance of waves in space plasmas : Examples from the auroral region and the magnetopause

    Författare :Gabriella Stenberg; Umeå universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; Space and plasma physics; Plasma waves; magnetospheric physics; magnetopause; auroral region; wave distribution function; space exploration; reconnection; current tubes; Rymd- och plasmafysik; Space physics; Rymdfysik; rymdfysik; Space Physics;

    Sammanfattning : This thesis discusses the reasons for space exploration and space science. Space plasma physics is identified as an essential building block to understand the space environment and it is argued that observation and analysis of space plasma waves is an important approach.Space plasma waves are the main actors in many important processes. LÄS MER

  5. 5. Numerical Simulation as a Tool for Studying Waves and Radiation in Space

    Författare :Lars Kristen Selberg Daldorff; Bo Thide; Francesco Califano; Uppsala universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; space physics; plasma physics; kinetic plasma; plasma simulations; beam instabilities; Space physics; Rymdfysik;

    Sammanfattning : Plasma physics governs the area of interactions between charged particles. As 99% of the visible universe is in a plasma state, it is an important topic in astronomy and space physics, where we already at an altitude of 60 km reach the plasma environment surrounding our planet in the form of the ionosphere. LÄS MER