Sökning: "Cluster spacecraft"
Visar resultat 1 - 5 av 19 avhandlingar innehållade orden Cluster spacecraft.
1. Magnetic Reconnection in Space Plasmas : Cluster Spacecraft Observations
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. Electron energization in near-Earth space : Studies of kinetic scales using multi-spacecraft data
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. Cluster Observations and Theoretical Explanations of Broadband Waves in the Auroral Region
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. 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. High altitude ion heating observed by the Cluster spacecraft
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
