Sökning: "auroral potential structures"

Hittade 3 avhandlingar innehållade orden auroral potential structures.

  1. 1. Investigations of auroral electric fields and currents

    Författare :Tommy Johansson; Göran Marklund; Kristina Lynch; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; auroral physics; auroral electric fields; auroral potential structures; auroral particle acceleration; Space physics; Rymdfysik;

    Sammanfattning : The Cluster spacecraft have been used to investigate auroral electric fields and field-aligned currents (FACs) at geocentric distances between 4 and 7 Re. The electric fields have been measured by the EFW instrument, consisting of two pairs of spherical probes, and the FACs have been calculated from measurements of the magnetic field by the FGM fluxgate magnetometer. LÄS MER

  3. 2. Multi-Spacecraft Observations of the Auroral Acceleration Region

    Författare :Soheil Sadeghi; Göran T. Marklund; Andris Vaivads; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : The two major agents for producing aurora are generally believed to be the quasi-static parallel electric fields, accelerating electrons in the auroral acceleration region (AAR), and Alfvén waves. The Cluster spacecraft quartet has made multi-spacecraft measurements in the AAR possible for the first time. LÄS MER

  4. 3. Cluster in situ studies of the auroral acceleration region

    Författare :Bin Li; Göran Marklund; Stein Haaland; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Cluster; Aurora acceleration region; Physics; Fysik;

    Sammanfattning : This thesis addresses a central topic in auroral physics, namely particle accelerationproducing intense aurora as well as energetic plasma outflow. Cluster satellitemeasurements of electric and magnetic fields, electrons and ions, collected across auroralfield lines, are used to study various aspects of the quasi-static auroral accelerationregion (AAR), its relation to the auroral density cavity, and the relative role of quasistaticand Alfvénic acceleration for producing aurora. LÄS MER