Sökning: "solar rotation"

Visar resultat 1 - 5 av 11 avhandlingar innehållade orden solar rotation.

1. 1. Combining Models of Coronal Mass Ejections and Solar Dynamos

   Författare :Jörn Warnecke; Axel Brandenburg; Juri Toomre; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Magnetohydrodynamics; convection; turbulence; solar dynamo; solar rotation; solar activity; coronal mass ejections; Astronomy; astronomi;

   Sammanfattning : Observations show that Coronal Mass Ejections (CMEs) are associated with twisted magnetic flux configurations. Conventionally, CMEs are modeled by shearing and twisting the footpoints of a certain distribution of magnetic flux at the solar surface and letting it evolve at the surface. LÄS MER

3. 2. Formation of solar bipolar regions : Magnetic flux concentrations from suction of the negative effective magnetic pressure instability

   Författare :Illa Rivero Losada; Axel Brandenburg; Matthias Rempel; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Magnetohydrodynamics MHD ; turbulence; dynamo; Sun: magnetic fields; Sun: rotation; Sun: activity; Sun: dynamo; Astronomy; astronomi;

   Sammanfattning : Sunspots stand out on the visible solar surface. They appear as dark structures evolving and changing over time. They host energetic and violent events, like coronal mass ejections and flares, and concentrate strong magnetic fields. LÄS MER

4. 3. Deployment Control of Spinning Space Webs and Membranes

   Författare :Mattias Gärdsback; Anders Eriksson; Gunnar Tibert; Thomas W. Murphey; KTH; []
   Nyckelord :Flexible structures; space webs; membranes; solar sails; solar power systems; deployment control; optimal control; centrifugal force deployment; spin deployment; rotation-free; shell elements; TECHNOLOGY; TEKNIKVETENSKAP;

   Sammanfattning : Future solar sail and solar power satellite missions require deployment of large and lightweight flexible structures in space. One option is to spin the assembly and use the centrifugal force for deployment, stiffening and stabilization. LÄS MER

5. 4. Solar Type Stars as Calibrators : A Photometric and Spectroscopic Study on the Atmospheric Properties of Late-type Stars

   Författare :Anna Önehag; Ulrike Heiter; Andreas Korn; Bengt Gustafsson; Frank Grundahl; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; stars: atmospheres; stars: late-type; techniques: photometric; stars: abundances; techniques: spectroscopic; Astronomy; Astronomi;

   Sammanfattning : Detailed knowledge of solar-type stars is essential in the understanding of the evolutionary past, presence and future of the Sun as well as the formation of its planetary system. Moreover, solar-type stars are of key significance for the study of the evolution of the Galaxy. The ages of solar-type stars map the full galactic evolution. LÄS MER

7. 5. The Dynamical Spin Vector Evolution of the Asteroids

   Författare :Erik Skoglöv; Karri Muinonen; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Astronomy; asteroids; Eros; Ceres; Vesta; dynamics; rotation; rotational dynamics; orbits; resonances; Astronomi; Astronomy and astrophysics; Astronomi och astrofysik; astronomi; Astronomy;

   Sammanfattning : The dynamical evolution of the spin axis direction due to gravitational and thermal factors is examined. It is found that the spin axis variations generally are regular and relatively small for the bodies in the asteroid main belt. There are also reasons to believe that this is the case for minor objects beyond the main belt. LÄS MER