Sökning: "Solar hydrodynamics"

Visar resultat 1 - 5 av 12 avhandlingar innehållade orden Solar hydrodynamics.

  1. 1. Origin of solar surface activity and sunspots

    Författare :Sarah Jabbari; Axel Brandenburg; Laurene Jouve; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Magneto-hydrodynamics; solar physics; dynamo theory; Astronomy; astronomi;

    Sammanfattning : Sunspots and active regions are two of the many manifestations of the solar magnetic field. This field plays an important role in causing phenomena such as coronal mass ejections, flares, and coronal heating. Therefore, it is important to study the origin of sunspots and active regions and determine the underlying mechanism which creates them. LÄS MER

  3. 2. From mean-field hydromagnetics to solar magnetic flux concentrations

    Författare :Koen Kemel; Axel Brandenburg; Alexander Ruzmaikin; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; magneto-hydrodynamics; solar physics; turbulence; Astronomy; astronomi;

    Sammanfattning : The main idea behind the work presented in this thesis is to investigate if it is possible to find a mechanism that leads to surface magnetic field concentrations and could operate under solar conditions without postulating the presence of magnetic flux tubes rising from the bottom of the convection zone, a commonly used yet physically problematic approach.In this context we study the ‘negative effective magnetic pressure effect’: it was pointed out in earlier work (Kleeorin et al. LÄS MER

  4. 3. The Formation of Giant Planets

    Författare :Michiel Lambrechts; Astronomi - Genomgår omorganisation; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Planet formation; Solar System; Exoplanets; Giant planets; Hydrodynamics;

    Sammanfattning : Giant planets form embedded in a protoplanetary disc around a young star. Close to the midplane a large fraction of the available mass in solids is found in particles of cm to dm in size, which drift towards the star due to friction with the surrounding gas. LÄS MER

  5. 4. A novel solar-driven system for two-step conversion of CO2 with ceria-based catalysts

    Författare :Bo Wei; Reza Fakhrai; Torsten Fransson; Nader Jand; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; CO2 conversion; solar; ceria; thermogravimetric test; exergy analysis; simulink; fluidized bed; gas-solid flow; simulation; Energiteknik; Energy Technology;

    Sammanfattning : Global warming is an unequivocal fact proved by the persistent rise of the average temperature of the earth. IPCC reported that scientists were more than 90 % certain that most of the global warming was caused by increasing concentrations of greenhouse gases (GHG) produced by human activities. LÄS MER

  7. 5. Turbulence-Assisted Planetary Growth : Hydrodynamical Simulations of Accretion Disks and Planet Formation

    Författare :Wladimir Lyra; Nikolai Piskunov; Thomas Henning; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; accretion; accretion disks; hydrodynamics; instabilities; methods: numerical; solar system: formation; planets and satellites: formation; magnetohydrodynamics MHD ; turbulence; diffusion; stars: planetary systems: formation; Astronomy and astrophysics; Astronomi och astrofysik;

    Sammanfattning : The current paradigm in planet formation theory is developed around a hierarquical growth of solid bodies, from interstellar dust grains to rocky planetary cores. A particularly difficult phase in the process is the growth from meter-size boulders to planetary embryos of the size of our Moon or Mars. LÄS MER