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  1. 1. Rosetta Observations of Plasma and Dust at Comet 67P

    Författare :Fredrik Leffe Johansson; Anders Eriksson; Jan-Erik Wahlund; Nicolas André; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Rosetta; Comets; Plasma; Langmuir Probes; Dust; Spacecraft-plasma interaction; Electrostatic Probes; Rosetta; kometer; plasma; stoft; rymdfarkost-plasma växelverkan; Fysik med inriktning mot rymd- och plasmafysik; Physics with specialization in Space and Plasma Physics;

    Sammanfattning : In-situ observations of cometary plasma are not made because they are easy. The historic ESA Rosetta mission was launched in 2004 and traversed space for ten years before arriving at comet 67P/Churyumov-Gerasimenko, which it studied in unprecedented detail for two years. LÄS MER

  2. 2. Rosetta spacecraft potential and activity evolution of comet 67P

    Författare :Elias Odelstad; Anders Eriksson; Arne Pedersen; Uppsala universitet; []
    Nyckelord :Rosetta; comet; 67P; RPC-LAP; RPC-MIP; Langmuir probe; spacecraft potential; plasma; Fysik med inriktning mot rymd- och plasmafysik; Physics with specialization in Space and Plasma Physics;

    Sammanfattning : The plasma environment of an active comet provides a unique setting for plasma physics research. The complex interaction of newly created cometary ions with the flowing plasma of the solar wind gives rise to a plethora of plasma physics phenomena, that can be studied over a large range of activity levels as the distance to the sun, and hence the influx of solar energy, varies. LÄS MER

  3. 3. Plasma environment of an intermediately active comet : Evolution and dynamics observed by ESA's Rosetta spacecraft at 67P/Churyumov-Gerasimenko

    Författare :Elias Odelstad; Anders Eriksson; Andrew Coates; Uppsala universitet; []
    Nyckelord :Rosetta; comet; 67P; RPC-LAP; RPC-MIP; RPC-ICA; RPC-MAG; ROSINA-COPS; Langmuir probe; spacecraft potential; plasma; Churyumov-Gerasimenko; ion composition analyzer; diamagnetic cavity; ion velocity; electron temperature; ion-neutral drag; collisional coupling; wake effects; filamentation; electron cooling; plasma waves; hybrid waves; Bernstein waves; minimum variance; polarization; wavelet; density fluctuations; magnetic field oscillations; drift-cyclotron instability; asymmetric plasma and magnetic field enhancements; Fysik med inriktning mot rymd- och plasmafysik; Physics with specialization in Space and Plasma Physics;

    Sammanfattning : The subject of this thesis is the evolution and dynamics of the plasma environment of a moderately active comet before, during and after its closest approach to the Sun. For over 2 years in 2014-2016, the European Space Agency’s Rosetta spacecraft followed the comet 67P/Churyumov-Gerasimenko at distances typically between a few tens and a few hundred kilometers from the nucleus, the longest and closest inspection of a comet ever made. LÄS MER

  4. 4. 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 :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

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

    Författare :Sofia Bergman; Gabriella Stenberg Wieser; Martin Wieser; Gert Brodin; Stein Håland; Umeå universitet; []
    Nyckelord :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