Search for dissertations about: "plasma sheath"

Showing result 1 - 5 of 17 swedish dissertations containing the words plasma sheath.

  1. 1. Modelling of cathode-plasma interaction in short high-intensity electric arc : Application to Gas Tungsten Arc Welding

    Author : Alireza Javidi Shirvan; Isabelle Choquet; Håkan Nilsson; Armelle Vardelle; Högskolan Väst; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; Electric arc discharge; sheath; pre-sheath; Knudsen layer; doped refractory cathode; arc-cathode coupling; Gas Tungsten Arc simulation; OpenFOAM.; Production Technology; Produktionsteknik; Manufacturing and materials engineering; Produktions- och materialteknik;

    Abstract : In arc welding the quality of the weld is strongly influenced by the thermal history of the workpiece which is itself governed by the electric arc heat source. The models for predicting weld properties thus need a good evaluation of the distribution of the heat input from thearc to the workpiece. READ MORE

  2. 2. Modelling of laser plasma interaction with applications to particle acceleration and radiation generation

    Author : Benjamin Svedung Wettervik; Chalmers tekniska högskola; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; plasma; ion acceleration; continuum methods; electron wakefield acceleration; raditation generation; coherent X-ray pulses; Vlasov-Maxwell equations;

    Abstract : The development of laser systems with ultra-high intensities has allowed the study of the relativistic interaction of laser light and ionized matter, plasmas, as well as opened up prospects for compact particle accelerators, generation of high intensity X-ray, XUV radiation, and probing QED-effects, which are present in the high intensity regime. To describe laser matter interaction, it is necessary to self-consistently account for the paths of a large number of particles and the corresponding electromagnetic fields, with the addition of stochastic effects at high laser intensities. READ MORE

  3. 3. Laser-Driven Particle Acceleration - Improving Performance Through Smart Target Design

    Author : Matthias Burza; Atomfysik; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; wakefield; ultra-relativistic; ultra-intense; TNSA; Terawatt; sheath; proton; polarimetry; plasma mirror; plasma; Petawatt; particle; oscillation; Normarski; micromachining; LWFA; laser; interferometry; electron; contrast; acceleration; bubble; Fysicumarkivet A:2012:Burza;

    Abstract : Laser-driven particle acceleration makes use of sub-picosecond, pulsed, high-power laser systems, capable of producing intensities ~10^{19} W/cm^2 at the laser focus to form plasmas, and use ultra-relativistic and nonlinear dynamics to produce quasistatic acceleration fields. This allows electrons to be accelerated to ~100 MeV over sub-centimetre distances, while protons may be accelerated to the ~10 MeV regime. READ MORE

  4. 4. Detector Development, Source Characterization and Novel Applications of Laser Ion Acceleration

    Author : Lovisa Senje; Atomfysik; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Laser; Ion; Acceleration; Proton; Water; Sheath; Lifetime; Laser; Ion; Acceleration; Proton; Water; Radiolysis; Sheath; Detector; Fysicumarkivet A:2017:Senje;

    Abstract : The main focus of the work presented in this thesis is on experimental studies oflaser acceleration of protons and other positive ions from solid targets. The topic is explored from three different angles: firstly, the development of diagnostics adapted to the ion pulses, secondly, the characterization of the source of the energetic particles and, finally, the application of laser-accelerated protons for time-resolved radiolysis of glass and water. READ MORE

  5. 5. Engineered ion-bombardment as a tool in thin film deposition

    Author : Rommel Paulo B. Viloan; Ulf Helmersson; Daniel Lundin; Rainer Hippler; Linköpings universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; HiPIMS; Bipolar HiPIMS; Ion-bombardment; Thin film;

    Abstract : Energetic-ion bombardment has become an attractive route to modify the crystal growth and deposit high quality thin films. In high-power impulse magnetron sputtering (HiPIMS) where the discharge is characterized by a significant amount of ions of the sputter-ejected atoms, energetic-ion bombardment effects could not be underestimated. READ MORE