Sökning: "Plasmafysik"

Visar resultat 1 - 5 av 83 avhandlingar innehållade ordet Plasmafysik.

  1. 1. Solitary waves and enhanced incoherent scatter ion lines

    Författare :Jonas Ekeberg; Lars Eliasson; Kristof Stasiewicz; Jan Trulsen; Umeå universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; plasma waves and instabilities; nonlinear phenomena; solitons and solitary waves; ionosphere; Sun: corona; incoherent scatter radar; MHD; plasmavågor och instabiliteter; ickelinjära fenomen; solitoner och solitära vågor; jonosfär; solen: korona; inkoherent spridningsradar; MHD; Geocosmophysics and plasma physics; Geokosmofysik och plasmafysik; Space physics; Rymdfysik; Plasma physics; Plasmafysik; Non-linear dynamics; chaos; Icke-linjär dynamik; kaos; fysik; Physics; rymd- och plasmafysik; Space and Plasma Physics;

    Sammanfattning : This thesis addresses solitary waves and their significance for auroral particle acceleration, coronal heating and incoherent scatter radar spectra. Solitary waves are formed due to a balance of nonlinear and dispersive effects. LÄS MER

  2. 2. Multi-spectral analysis of fine scale aurora

    Författare :Hanna Dahlgren; Göran Marklund; Nickolay Ivchenko; Fred Sigernes; KTH; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; Plasma physics; Plasmafysik; Optics; Optik;

    Sammanfattning : The Aurora Borealis is the visible manifestation of the complex plasma interaction between the solar wind and the Earth's magnetosphere and ionosphere. Ground based and in situ measurements demonstrate a prevalence of dynamic fine structure within auroral displays, with spatial scales down to tens of metres and time variations occurring on a fraction of a second. LÄS MER

  3. 3. High Power Microwave Sources : design and experiments

    Författare :Cecilia Möller; Nils Brenning; Stefan Silfverskiöld; KTH; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; Space physics; Rymdfysik; Plasma physics; Plasmafysik;

    Sammanfattning : High-Power Microwaves (HPM) can be used to intentionally disturb or destroy electronic equipment at a distance by inducing high voltages and currents. This thesis presents results from experiments with a narrow band HPM source, the vircator. LÄS MER

  4. 4. Waves and instabilities in quantum plasmas

    Författare :Shahid Ali; Padma Kant Shukla; Mattias Marklund; Jose Tito Mendonca; Umeå universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; Quantum mechanical effects; dusty plasma; linear and nonlinear waves; instabilities; nonlinear wave interactions; density gradients; magnetoplasmas.; Plasma physics; Plasmafysik;

    Sammanfattning : The study of waves and instabilities in quantum plasmas is of fundamental importance for understanding collective interactions in superdense astrophysical objects, in high intense laser-plasma/solid-matter interactions, in microelectronic devices and metallic nanostructures. In dense quantum plasmas, there are new pressure laws associated with the Fermi-Dirac distribution functions and new quantum forces associated with the quantum Bohm potential and the Bohr magnetization involving electron ½ spin. LÄS MER

  5. 5. Gravitational perturbations in plasmas and cosmology

    Författare :Mats Forsberg; Gert Brodin; Michael Bradley; Christopher Clarkson; Umeå universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; general relativity; cosmology; gravitational waves; plasma; electromagnetic waves; nonlinear waves; Plasma physics; Plasmafysik; Theory of relativity; gravitation; Relativitetsteori; gravitation; Cosmology; Kosmologi; teoretisk fysik; Theoretical Physics;

    Sammanfattning : Gravitational perturbations can be in the form of scalars, vectors or tensors. This thesis focuses on the evolution of scalar perturbations in cosmology, and interactions between tensor perturbations, in the form of gravitational waves, and plasma waves. LÄS MER