Sökning: "Space and plasma physics"

Visar resultat 16 - 20 av 246 avhandlingar innehållade orden Space and plasma physics.

  1. 16. There and back again... An Earth magneto-tale : understanding plasma flows in the magnetotail

    Författare :Alexandre De Spiegeleer; Maria Hamrin; Herbert Gunell; Timo Pitkänen; Colin Forsyth; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Plasma dynamics; Earth magnetosphere; magnetotail; plasma sheet flows; oscillatory flows; burst bulk flows; tailward flows; rymdfysik; Space Physics; rymd- och plasmafysik; Space and Plasma Physics;

    Sammanfattning : On average, the Earth's magnetotail plasma sheet seems to be a calm region of the magnetosphere where the plasma moves slowly towards Earth. However, the plasma sheet actually hosts many phenomena, some of which can affect Earth. LÄS MER

  2. 17. Modelling of laser plasma interaction with applications

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

    Sammanfattning : The development of laser systems with ultra-high intensities has both opened up prospects for compact particle accelerators, as well as 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. LÄS MER

  3. 18. Escape to space or return to venus : ion flows measured by venus express

    Författare :Moa Persson; Yoshifumi Futaana; Hans Nilsson; Maria Hamrin; Dmitrij Titov; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Venus; water; escape; planetary physics; oxygen; O ; hydrogen; H ; ions; space physics; space plasma physics; Venus Express; ASPERA-4; IMA; spacecraft measurements; rymd- och plasmafysik; Space and Plasma Physics;

    Sammanfattning : The present-day Venusian atmosphere is crushingly dense, extremely hot and arid. Yet, in its early history, Venus presumably had a massive amount of water, which, if spread evenly over the surface, provided a water depth of 10s to 100s of meters. Therefore, over the course of the atmospheric evolution, the water must have been removed from Venus. LÄS MER

  4. 19. Gyrokinetic simulations of turbulent transport in tokamak plasmas

    Författare :Andreas Skyman; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; fusion; TEM; ITG; tokamaks; e-science; Joint European Torus; turbulence; gyrokinetics; plasma physics; impurity transport;

    Sammanfattning : With the enormous growth of high performance computing (HPC) over the last few decades, plasma physicists have gained access to a valuable instrument for investigating turbulent plasma behaviour. In this thesis, these tools are utilised for the study of particle transport in fusion devices of the tokamak variety. LÄS MER

  5. 20. Plasma Interactions with Icy Bodies in the Solar System

    Författare :Jesper Lindkvist; Mats Holmström; Martin Wieser; Elias Roussos; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; plasma interactions; icy bodies; solar system; space physics; plasma physics; hybrid model; numerical model; solar wind; magnetosphere; sub-Alfvénic; subsonic; non-collisional; atmosphereless; exosphere; coma; subsurface ocean; induction; magnetic dipole; pick-up ion; mass-loading; moon; natural satellite; dwarf planet; comet; Jupiter; Jovian; Callisto; Ceres; 67P; Churyumov-Gerasimenko; rymd- och plasmafysik; Space and Plasma Physics;

    Sammanfattning : Here I study the “plasma interactions with icy bodies in the solar system”, that is, my quest to understand the fundamental processes that govern such interactions. By using numerical modelling combined with in situ observations, one can infer the internal structure of icy bodies and their plasma environments. LÄS MER