Sökning: "auroral electric fields"
Visar resultat 1 - 5 av 12 avhandlingar innehållade orden auroral electric fields.
1. Investigations of auroral electric fields and currents
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
2. Auroral Electric Fields From Satellite Observations and Numerical Modelling
Sammanfattning : This thesis is about electrodynamics of thehigh-latitude/auroral region of near-Earth space. The work ismainly based on electric field measurements made by the doubleprobe instrument on the Freja satellite at altitudes ofapproximately 800-1700 km, together with measurements fromother instruments on the same satellite, and ground-basedinstrumentation. LÄS MER
3. Numerical modeling of auroral processes
Sammanfattning : One of the most conspicuous problems in space physics for the last decades has been to theoretically describe how the large parallel electric fields on auroral field lines can be generated. There is strong observational evidence of such electric fields, and stationary theory supports the need for electric fields accelerating electrons to the ionosphere where they generate auroras. LÄS MER
4. Cluster investigations of the extent and altitude distribution of the auroral density cavity
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. Global Magnetospheric Plasma Convection
Sammanfattning : This thesis deals with the global aspects of plasmaconvection in the magnetosphere as measured by the low-altitudepolar orbiting Astrid-2 and FAST satellites. The major focus ison the electric field measurements, but they are alsocomplemented by magnetic field, ion and electron particle data,which is fundamental for the understanding of theelectrodynamics of the high-latitude auroral ovals and polarcap, which are the regions analysed here. LÄS MER
