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  1. 1. High-Order Harmonics- Characterisation, Optimisation and Applications

    Författare :Claire Lyngå; Atomfysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; high-harmonic generation; VUV spectroscopy; high-power lasers; Atomic and molecular physics; radiative lifetimes; XUV spectroscopy; Atom- och molekylärfysik; Fysicumarkivet A:1999:Lyngå;

    Sammanfattning : Recent advances in laser technology, with the development of extremely short-pulse, high-intensity lasers, have opened doors to new areas in atomic physics. By focusing light from an intense, short-pulse laser into a gas jet, the emission of high-order harmonics of the laser frequency has been studied. LÄS MER

  3. 2. Optimisation and Application of Intense High-Order Harmonic Pulses

    Författare :Lena Roos; Atomfysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Coherent radiation; Optimisation; Multiphoton ionisation; Phase matching; Physics; Fysik; Atomic and molecular physics; Atom- och molekylärfysik; Laserteknik; Laser technology; High-power lasers; Short pulses; High-order harmonic generation; Short wavelength; Fysicumarkivet A:2001:Roos;

    Sammanfattning : The high-order harmonics that are created in the interaction between an intense laser pulse (around 1014 W/cm2) and a gas medium are studied. The high-order harmonic radiation is a relatively new source of coherent radiation in the short wavelength range. LÄS MER

  4. 3. Stable High-Order Finite Difference Methods for Aerodynamics

    Författare :Magnus Svärd; Jan Nordström; Thomas Hagstrom; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; finite difference methods; high-order accuracy; summation-by-parts; stability; energy estimates; finite volume methods; Numerical analysis; Numerisk analys; Scientific Computing; Beräkningsvetenskap; Numerical Analysis;

    Sammanfattning : In this thesis, the numerical solution of time-dependent partial differential equations (PDE) is studied. In particular high-order finite difference methods on Summation-by-parts (SBP) form are analysed and applied to model problems as well as the PDEs governing aerodynamics. LÄS MER

  5. 4. High Order Symmetric Finite Difference Schemes for the Acoustic Wave Equation

    Författare :Abraham Zemui; Bertil Gustafsson; Leif Abrahamsson; Per Weinerfelt; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; finite element method; mass lumping; high order; finite difference method; wave equation; Numerical Analysis; Numerisk analys;

    Sammanfattning : When someone speaks, or when a piano is played, sound waves are spread through the room. Physically the propagation of sound is governed by the acoustic wave equation. This thesis deals with the problem of finding solutions to this equation by numerical methods. LÄS MER

  7. 5. Generation of coherent short-wavelength radiation --- High-order harmonics and x-ray lasers

    Författare :Tomas Starczewski; Atomfysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Atomic and molecular physics; short-wavelength radiation; coherence; high-intensity lasers; high-order harmonics; x-ray lasers; Atom- och molekylärfysik;

    Sammanfattning : The recent availability of short-pulse, high-intensity, compact lasers has opened doors to new and fascinating areas in atomic physics. Using the Lund Terawatt Laser, the interaction of femtosecond, near-infrared and visible laser radiation with matter at intensities in the range 1013--1017 W/cm2 was studied. LÄS MER