Sökning: "Cluster spacecraft"

Visar resultat 1 - 5 av 19 avhandlingar innehållade orden Cluster spacecraft.

  1. 1. Magnetic Reconnection in Space Plasmas Cluster Spacecraft Observations

    Detta är en avhandling från Uppsala : Acta Universitatis Upsaliensis

    Författare :Alessandro Retinò; Uppsala universitet.; [2007]
    Nyckelord :Space and plasma physics; space physics; plasma astrophysics; plasma physics; transport processes; boundary layers; magnetic reconnection; turbulence; particle acceleration; solar system; magnetospheres; Rymd- och plasmafysik;

    Sammanfattning : Magnetic reconnection is a universal process occurring at boundaries between magnetized plasmas, where changes in the topology of the magnetic field lead to the transport of charged particles across the boundaries and to the conversion of electromagnetic energy into kinetic and thermal energy of the particles. Reconnection occurs in laboratory plasmas, in solar system plasmas and it is considered to play a key role in many other space environments such as magnetized stars and accretion disks around stars and planets under formation. LÄS MER

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

    Detta är en avhandling från Uppsala : Acta Universitatis Upsaliensis

    Författare :Elin Eriksson; Uppsala universitet.; Uppsala universitet.; [2018]
    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

  3. 3. Cluster Observations and Theoretical Explanations of Broadband Waves in the Auroral Region

    Detta är en avhandling från Uppsala : Acta Universitatis Upsaliensis

    Författare :Marie Backrud; Uppsala universitet.; [2005]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Space and plasma physics; ion acoustic waves; auroral region; anomalous resistivity; Cluster; Rymd- och plasmafysik; NATURAL SCIENCES Physics Geocosmophysics and plasma physics Space physics; NATURVETENSKAP Fysik Geokosmofysik och plasmafysik Rymdfysik;

    Sammanfattning : Broadband extremely low-frequency wave emissions below the ion plasma frequency have been observed by a number of spacecraft and rockets on auroral field lines. The importance of these broadband emissions for transverse ion heating and electron acceleration in the auroral regions is now reasonably well established. LÄS MER

  4. 4. Cluster investigations of the extent and altitude distribution of the auroral density cavity

    Detta är en avhandling från Stockholm : KTH Royal Institute of Technology

    Författare :Love Alm; KTH.; [2015]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Auroral density cavity; auroral accelaration; Cluster; in situ observation; electron density; pseudo altitude; Physics; Fysik;

    Sammanfattning : The auroral density cavity constitutes the boundary between the cold, dense ionospheric plasma and the hot, tenuous plasma sheet plasma. The auroral density cavity is characterized by low electron density and particle populations modified by parallel electric fields. LÄS MER

  5. 5. High altitude ion heating observed by the Cluster spacecraft

    Detta är en avhandling från Umeå : Umeå universitet, Institutionen för fysik

    Författare :Martin Waara; Umeå universitet.; [2011]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURAL SCIENCES Physics Geocosmophysics and plasma physics Space physics; NATURVETENSKAP Fysik Geokosmofysik och plasmafysik Rymdfysik; rymd- och plasmafysik; Space and Plasma Physics;

    Sammanfattning : This thesis deals with heating of outowing oxygen ions at high altitude above the polar cap using data from the Cluster spacecraft. oInospheric plasma may flow up from the ionosphere but at velocities which are low enough that the ions are still gravitationally bound. For the ions to overcome gravity, further acceleration is needed. LÄS MER