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Visar resultat 1 - 5 av 15 avhandlingar som matchar ovanstående sökkriterier.

  1. 1. Automorphic forms and string theory: Small automorphic representations and non-perturbative effects

    Författare :Henrik Gustafsson; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; instantons; automorphic forms; automorphic representations; Eisenstein series; U-duality; non-perturbative effects; string theory;

    Sammanfattning : This compilation thesis stems from a project with the purpose of determining non-perturbative contributions to scattering amplitudes in string theory carrying important information about instantons, black hole quantum states and M-theory. The scattering amplitudes are functions on the moduli space invariant under the discrete U-duality group and this invariance is one of the defining properties of an automorphic form. LÄS MER

  3. 2. Drift Waves in General Toroidal Equilibria

    Författare :Johan Anderson; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; fusion plasmas; instabilities; toroidal geometry; drift waves;

    Sammanfattning : One of the main concerns in fusion research is to understand the anomalously high transport in magnetically confined plasmas. In recent years, substantial progress in the understanding of transport in terms of drift waves in fusion plasmas has been achieved. LÄS MER

  4. 3. Buoy Geometry, Size and Hydrodynamics for Power Take Off Device for Point Absorber Linear Wave Energy Converter

    Författare :Halvar Gravråkmo; Mats Leijon; Jan Isberg; Luke Myers; Uppsala universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; point absorber; wave; energy; converter; ocean; wec; toroidal; buoy; torus; cylindrical; cylinder; experiment; full scale; trial; sea; energy; renewable; Engineering Science with specialization in Science of Electricity; Teknisk fysik med inriktning mot elektricitetslära;

    Sammanfattning : Wave energy converters of point absorber type have been developed and constructed. Full scale experiments have been carried out at sea and electricity has been successfully delivered. Linear permanent magnet generators together with a subsea substation and buoys of various geometric shapes have been investigated theoretically and experimentally. LÄS MER

  5. 4. Drift waves in non-circular tokamak geometry

    Författare :Johan Anderson; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; tokamak geometry; instabilities; drift waves; fusion plasmas;

    Sammanfattning : One of the main concerns in fusion research is to understand the anomalously high transport in magnetically confined plasmas. In recent years, substantial progress in the understanding of transport in terms of drift waves in tokamaks has been achieved. LÄS MER

  7. 5. Influence of Geometry on Drift Waves in Tokamaks and Stellarators

    Författare :Tariq Rafiq; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; ITG; local magnetic shear; linear instabilities; drift waves;

    Sammanfattning : There is a general consensus that drift waves are responsible for a large amount of transport in fusion experiments and it is of importance to investigate their linear stability and nonlinear evolution. These instabilities have therefore been intensively investigated in tokamaks for the last few decades. LÄS MER