Sökning: "Sunspots"

Visar resultat 1 - 5 av 13 avhandlingar innehållade ordet Sunspots.

1. 1. Imaging spectropolarimetry of solar active regions

   Författare :Gautam Narayan; Göran Scharmer; Rolf Schlichenmaier; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Sun; Spectropolarimetry; Solar magnetic fields; Sunspots; Plages; Solar physics; Solfysik; Astronomy; astronomi;

   Sammanfattning : Solar magnetic fields span a wide range of spatial scales from sunspots and plages to magnetic bright points. A clear understanding of the physical processes underlying the evolution of these magnetic features requires high-resolution spectropolarimetric observations of solar active regions and comparisons with synthetic data from simulations. LÄS MER

3. 2. Three-dimensional mapping of fine structure in the solar atmosphere

   Författare :Vasco M. J. Henriques; Dan Kiselman; Göran Scharmer; Hector Socas-Navarro; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Sun; sunspots; Swedish 1-meter Solar Telescope; active regions; image processing; sunspot penumbra; Astronomy; astronomi;

   Sammanfattning : The effects on image formation through a tilted interference filter in a converging beam are investigated and an adequate compensation procedure is established. A method that compensates for small-scale seeing distortions is also developed with the aim of co-aligning non-simultaneous solar images from different passbands. LÄS MER

4. 3. The dynamic chromosphere : Results and techniques with an observational approach

   Författare :Carolina Robustini; Jorrit Leenaarts; Fernando Moreno Insertis; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Sun; chromosphere; jets; sunspots; imaging; spectropolarimetry; Astronomy; astronomi;

   Sammanfattning : The chromosphere is a critical interface between the relatively cold photosphere and the hot corona. Its landscape is rich in very dynamic phenomena such as jets, spicules, and surges, which are thought to play an important role in the heating of the Sun’s upper atmosphere. LÄS MER

5. 4. Origin of solar surface activity and sunspots

   Författare :SARAH JABBARI; AXEL BRANDENBURG; Vasilis Archontis; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Sun-Solar activity-Sunspots; teoretisk astrofysik; Theoretical Astrophysics;

   Sammanfattning : In the last few years, there has been significant progress in the development of a new model for explaining magnetic flux concentrations, by invoking the negative effective magnetic pressure instability (NEMPI) in a highly stratified turbulent plasma. According to this model, the suppression of the turbulent pressure by a large-scale magnetic field leads to a negative contribution of turbulence to the effective magnetic pressure (the sum of non-turbulent and turbulent contributions). LÄS MER

7. 5. 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