Sökning: "Gert Brodin"

Visar resultat 1 - 5 av 10 avhandlingar innehållade orden Gert Brodin.

  1. 1. Low-energy ions around comet 67P/Churyumov-Gerasimenko

    Författare :Sofia Bergman; Gabriella Stenberg Wieser; Martin Wieser; Gert Brodin; Stein Håland; Umeå universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; Low-energy ions; spacecraft charging; comets; 67P Churyumov-Gerasimenko; Rosetta; RPC-ICA; SPIS; diamagnetic cavity; field of view; plasma; space plasma physics; rymd- och plasmafysik; Space and Plasma Physics;

    Sammanfattning : Low-energy ions play important roles in the formation of the plasma environment around a comet. Reliable ways of measuring these ions are therefore of high importance to fully understand the processes and dynamics of this environment. Unfortunately, low-energy ions are infamously difficult to detect. LÄS MER

  2. 2. The effect of spacecraft charging on low-energy ion measurements around comet 67P/Churyumov-Gerasimenko

    Författare :Sofia Bergman; Gabriella Stenberg Wieser; Martin Wieser; Gert Brodin; Umeå universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; Spacecraft charging; low-energy ions; space physics; plasma physics; comet; Rosetta; SPIS; rymd- och plasmafysik; Space and Plasma Physics;

    Sammanfattning : A spacecraft in space interacts with the surrounding environment and aqcuires an electrostatic potential. Charged particles are constantly bombarding the surface of the spacecraft, and at the same time solar EUV radiation induces photoemission, causing electrons to be emitted from the surface. LÄS MER

  3. 3. Quantum Kinetic Theory for Plasmas : spin, exchange, and particle dispersive effects

    Författare :Robin Ekman; Gert Brodin; Jens Zamanian; Bengt Eliasson; Umeå universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; teoretisk fysik; Theoretical Physics;

    Sammanfattning : This thesis is about developing and studying quantum mechanical models of plasmas. Quantum effects can be important at high densities, at low temperatures, and in strong electromagnetic fields, in various laboratory and astrophysical systems. LÄS MER

  4. 4. Perturbative Methods in General Relativity

    Författare :Daniel Eriksson; Michael Bradley; Gert Brodin; Lászlo Árpád Gergely; Umeå universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; General relativity; perturbation theory; photon-photon scattering; cosmology; FRW models with cosmological constant; Bianchi type V; slowly rotating stars; Hartle formalism; Physics; Fysik;

    Sammanfattning : Einstein's theory of general relativity is a cornerstone in the process of gaining increased understanding about problems of gravitational nature. It can be applied to problems on the huge length scales of cosmology and as far as we know it does not break down before the Planck scale is approached. LÄS MER

  5. 5. Gravitational perturbations in plasmas and cosmology

    Författare :Mats Forsberg; Gert Brodin; Michael Bradley; Christopher Clarkson; Umeå universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; general relativity; cosmology; gravitational waves; plasma; electromagnetic waves; nonlinear waves; Plasma physics; Plasmafysik; Theory of relativity; gravitation; Relativitetsteori; gravitation; Cosmology; Kosmologi; teoretisk fysik; Theoretical Physics;

    Sammanfattning : Gravitational perturbations can be in the form of scalars, vectors or tensors. This thesis focuses on the evolution of scalar perturbations in cosmology, and interactions between tensor perturbations, in the form of gravitational waves, and plasma waves. LÄS MER