Sökning: "Andris Vaivads"

Visar resultat 1 - 5 av 13 avhandlingar innehållade orden Andris Vaivads.

  1. 1. Dissipation at the Earth's Quasi-Parallel Bow Shock

    Författare :Rico Behlke; Mats André; Harald Kucharek; Andris Vaivads; Manfred Scholer; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Space and plasma physics; collisionless shocks; wave-particle interactions; nonlinear phenomena; cross-shock potential; Cluster spacecraft; Rymd- och plasmafysik; Space physics; Rymdfysik;

    Sammanfattning : The Earth's bow shock is a boundary where the solar wind becomes decelerated from supersonic to subsonic speed before being deflected around the Earth. This thesis presents measurements by the Cluster spacecraft upstream and at the Earth's quasi-parallel bow shock where the angle between the upstream magnetic field and the bow shock normal is less than 45 degrees. LÄS MER

  3. 2. 3D Magnetic Nulls and Regions of Strong Current in the Earth's Magnetosphere

    Författare :Elin Eriksson; Andris Vaivads; Hans Nilsson; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Magnetic Nulls; Particle Acceleration; Current sheets; Magnetic reconnection; Magnetosphere; Fysik med inriktning mot rymd- och plasmafysik; Physics with specialization in Space and Plasma Physics;

    Sammanfattning : Plasma, a gas of charged particles exhibiting collective behaviour, can be found everywhere in our vast Universe. The characteristics of plasma in very distant parts of the Universe can be similar to characteristics in our solar system and near-Earth space. LÄS MER

  4. 3. Electron energization in near-Earth space : Studies of kinetic scales using multi-spacecraft data

    Författare :Elin Eriksson; Andris Vaivads; Masahiro Hoshino; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; magnetic reconnection; electron acceleration; electron heating; magnetosheath; magnetotail; magnetic nulls; Cluster; Magnetospheric MultiScale; Fysik med inriktning mot rymd- och plasmafysik; Physics with specialization in Space and Plasma Physics;

    Sammanfattning : Plasma, a gas of charged particles exhibiting collective behavior, is everywhere in the Universe. The heating of plasma to millions of degrees and acceleration of charged particles to very high energies has been observed in many astrophysical environments. How and where the heating and acceleration occur is in many cases unclear. LÄS MER

  5. 4. Ion dynamics and structure of collisionless shocks

    Författare :Andreas Johlander; Andris Vaivads; Rami Vainio; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : Shock waves are responsible for slowing down and heating supersonic flows. In collisionless space plasmas, shocks are able to accelerate particles to very high energies. We study injection of suprathermal ions at Earth’s quasi- parallel shock using high time resolution data from the Cluster spacecraft. LÄS MER

  7. 5. Ion dynamics and structure of collisionless shocks in space

    Författare :Andreas Johlander; Andris Vaivads; Robert F. Wimmer-Schweingruber; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Fysik med inriktning mot rymd- och plasmafysik; Physics with specialization in Space and Plasma Physics;

    Sammanfattning : Shock waves form when supersonic flows encounter an obstacle. Like in regular gases, shock waves can form in a plasma - a gas of electrically charged particles. Shock waves in plasmas where collisions between particles are very rare are referred to as collisionless shock waves. LÄS MER