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Visar resultat 1 - 5 av 26 avhandlingar som matchar ovanstående sökkriterier.

  1. 1. Theoretical Atomic Spectroscopy of Earthbound and Stellar Plasma

    Författare :Jon Grumer; Matematisk fysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; atomstruktur; atomära processer; elektronkorrelation; plasmaspektroskopi; magnetfält; hyperfinstruktur; solkoronan; rymdväder; förekomst av grundämnen i stjärnor; datorsimuleringar; Zeemaneffekt; relativistiska effekter; atomic structure; atomic processes; computer simulation; electron correlation; relativistic atomic theory; plasma spectroscopy; Zeeman effect; magnetic fields; hyperfine structure; solar corona; space weather; stellar abundances; Fysicumarkivet A:2016:Grumer;

    Sammanfattning : Motivated by spectroscopic analysis of astrophysical and laboratory plasma, this thesis concerns the fundamental structure and spectral properties of atoms and their ions. The multiconfiguration Dirac-Hartree-Fock (MCDHF) method is used to predict the emission or absorption of radiation, by atomic systems in general, and of heavy and highly charged ions in particular. LÄS MER

  3. 2. Kinetic modelling of runaway in plasmas

    Författare :Ola Embréus; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Fokker-Planck equation; synchrotron radiation; plasma; runaway; bremsstrahlung; Boltzmann equation;

    Sammanfattning : The phenomenon of runaway occurs in plasmas in the presence of a strong electric field, which overcomes the collisional friction acting on the charged particles moving through the plasma. A subpopulation of particles can then be accelerated to energies significantly higher than the thermal energy. LÄS MER

  4. 3. Plasma cloud penetration across magnetic boundaries

    Författare :Tomas Hurtig; KTH; []
    Nyckelord :Laboratory plasma experiments; Particle in cell simulation; Anomalous resistivity; Fast magnetic field diffusion; Anomalous particle transport;

    Sammanfattning : .... LÄS MER

  5. 4. Ultra-intense laser-plasma interaction for applied and fundamental physics

    Författare :Arkady Gonoskov; Mattias Marklund; Gert Brodin; Vladimir Tikhonchuk; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; ultra-intense laser; femtosecond pulse; plasma; relativistic phenomena; laser-driven acceleration; attosecond pulse generation; radiation reaction; fysik; Physics;

    Sammanfattning : Rapid progress in ultra-intense laser technology has resulted in intensity levels surpassing 1022 W/cm2, reaching the highest possible density of electromagnetic energy amongst all controlled sources available in the laboratory. During recent decades, fast growth in available intensity has stimulated numerous studies based on the use of high intensity lasers as a unique tool for the initiation of nonlinear behavior in various basic systems: first molecules and atoms, then plasma resulting from the ionization of gases and solids, and, finally, pure vacuum. LÄS MER

  7. 5. Experimental studies of materials migration in magnetic confinement fusion devices : Novel methods for measurement of macro particle migration, transport of atomic impurities and characterization of exposed surfaces

    Författare :Igor Bykov; Henric Bergsåker; Matej Mayer; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; fusion; tokamak; RFP; divertor; limiter; SOL; transport; migration; surface analysis; IBA; ion micro beam; beryllium; tritium; Physics; Fysik;

    Sammanfattning : During several decades of research and development in the field of Magnetically Confined Fusion (MCF) the preferred selection of materials for Plasma Facing Components (PFC) has changed repeatedly. Without doubt, endurance of the first wall will decide research availability and lifespan of the first International Thermonuclear Research Reactor (ITER). LÄS MER