Search for dissertations about: "comet"

Showing result 1 - 5 of 53 swedish dissertations containing the word comet.

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

    Author : Elias Odelstad; Anders Eriksson; Andrew Coates; Uppsala universitet; []
    Keywords : 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;

    Abstract : 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. READ MORE

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

    Author : Elias Odelstad; Anders Eriksson; Arne Pedersen; Uppsala universitet; []
    Keywords : 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;

    Abstract : 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. READ MORE

  3. 3. Evolving the Methodology for Detection of Primary DNA Damage : Development, adaptation and assessment of the single cell gel electrophoresis (comet) assay

    Author : Erik Bivehed; Björn Hellman; Hanna Karlsson; Uppsala universitet; []
    Keywords : MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Comet assay; DNA damage; DNA strand breaks; Flash-comet; Genotoxicity; In vitro; Single cell gel electrophoresis; Polymerase assisted DNA damage assay PADDA ; TK6 cells; UCDAS; U937 cells; Toxikologi; Toxicology; Farmaceutisk vetenskap; Pharmaceutical Science;

    Abstract : Deoxyribonucleic acid (DNA) is one of the most important molecules in nature. It is the fundamental carrier of evolutionary information and constitutes the genetic blueprint of all living organisms. Being the sole source of information, it is vital for the cell to transmit the correct genetic information from generation to generation. READ MORE

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

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

    Abstract : 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. READ MORE

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

    Author : Jesper Lindkvist; Mats Holmström; Martin Wieser; Elias Roussos; Umeå universitet; []
    Keywords : 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;

    Abstract : 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. READ MORE