Sökning: "plasma waves"

Visar resultat 11 - 15 av 98 avhandlingar innehållade orden plasma waves.

1. 11. Waves and instabilities in quantum plasmas

   Författare :Shahid Ali; Padma Kant Shukla; Mattias Marklund; Jose Tito Mendonca; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Quantum mechanical effects; dusty plasma; linear and nonlinear waves; instabilities; nonlinear wave interactions; density gradients; magnetoplasmas.; Plasma physics; Plasmafysik;

   Sammanfattning : The study of waves and instabilities in quantum plasmas is of fundamental importance for understanding collective interactions in superdense astrophysical objects, in high intense laser-plasma/solid-matter interactions, in microelectronic devices and metallic nanostructures. In dense quantum plasmas, there are new pressure laws associated with the Fermi-Dirac distribution functions and new quantum forces associated with the quantum Bohm potential and the Bohr magnetization involving electron ½ spin. LÄS MER

3. 12. The importance of waves in space plasmas : Examples from the auroral region and the magnetopause

   Författare :Gabriella Stenberg; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Space and plasma physics; Plasma waves; magnetospheric physics; magnetopause; auroral region; wave distribution function; space exploration; reconnection; current tubes; Rymd- och plasmafysik; Space physics; Rymdfysik; rymdfysik; Space Physics;

   Sammanfattning : This thesis discusses the reasons for space exploration and space science. Space plasma physics is identified as an essential building block to understand the space environment and it is argued that observation and analysis of space plasma waves is an important approach.Space plasma waves are the main actors in many important processes. LÄS MER

4. 13. Numerical Simulation as a Tool for Studying Waves and Radiation in Space

   Författare :Lars Kristen Selberg Daldorff; Bo Thide; Francesco Califano; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; space physics; plasma physics; kinetic plasma; plasma simulations; beam instabilities; Space physics; Rymdfysik;

   Sammanfattning : Plasma physics governs the area of interactions between charged particles. As 99% of the visible universe is in a plasma state, it is an important topic in astronomy and space physics, where we already at an altitude of 60 km reach the plasma environment surrounding our planet in the form of the ionosphere. LÄS MER

5. 14. VLF and ULF Waves Associated with Magnetospheric Substorms

   Författare :Andrew Collier; Lars Blomberg; James McKenzie; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Space physics; Subtorms; Magnetosphere; VLF waves; ULF waves; Space physics; Rymdfysik;

   Sammanfattning : A magnetospheric substorm is manifested in a variety of phenomena observed both in space and on the ground. Two electromagnetic signatures are the Substorm Chorus Event (SCE) and Pi2 pulsations. The SCE is a Very Low Frequency (VLF) radio phenomenon observed on the ground after the onset of the substorm expansion phase. LÄS MER

7. 15. Alfvén Waves and Energy Transformation in Space Plasmas

   Författare :Yuri Khotyaintsev; Kalevi Mursula; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Space and plasma physics; Alfvén waves; particle acceleration; ionosphere; magnetopause; magnetic reconnection; Rymd- och plasmafysik; Space physics; Rymdfysik; Space Physics; rymdfysik;

   Sammanfattning : This thesis is focused on the role of Alfvén waves in the energy transformation and transport in the magnetosphere. Different aspects of Alfvén wave generation, propagation and dissipation are considered. The study involves analysis of experimental data from the Freja, Polar and Cluster spacecraft, as well as theoretical development. LÄS MER