Sökning: "Jorrit Leenaarts"

Hittade 4 avhandlingar innehållade orden Jorrit Leenaarts.

  1. 1. The synthetic chromosphere : Results and techniques with a numerical approach

    Författare :Johan Pires Bjørgen; Jorrit Leenaarts; Oskar Steiner; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Sun; chromosphere; radiative transfer; numerical method; Astronomy; astronomi;

    Sammanfattning : Realistic numerical simulations of the solar atmosphere can be used to interpret different phenomena observed on the solar surface. To gain insight into the atmospheric physical conditions, we compare the observations with 3D radiative magnetohydrodynamic models combined with forward modeling (radiative transfer). LÄS MER

  2. 2. A multiwavelength approach to solar chromospheric heating : New insights from the millimeter continuum

    Författare :João Manuel da Silva Santos; Jaime de le Cruz Rodríguez; Jorrit Leenaarts; Petr Heinzel; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Sun; chromosphere; radiative transfer; waves; reconnection; Astronomy; astronomi;

    Sammanfattning : The chromosphere is an intermediate layer of the Sun's atmosphere where radiative equilibrium breaks down. The standard chromospheric diagnostics such as the Mg II h and k and Ca II H and K spectral lines are formed under nonlocal thermodynamic equilibrium (NLTE) and they are only partially sensitive to the local conditions. LÄS MER

  3. 3. The diagnostic potential of the He I D3 spectral line in the solar atmosphere

    Författare :Tine Libbrecht; Jaime de la Cruz Rodríguez; Jorrit Leenaarts; Göran Scharmer; Valentín Martínez Pillet; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Sun; Line formation; Chromosphere; Spectro-Polarimetry; Flares; Reconnection; Astronomy; astronomi;

    Sammanfattning : The research question of my PhD is in a way a simple one: what can observations of the He I D3 line teach us about the solar chromosphere? This optical spectral line at 5876 Å is generally formed in the upper chromosphere, and is sensitive to the local magnetic field. The He I D3 line is also indirectly sensitive to heating of the transition region and corona, since it is resulting from a transition that occurs between levels in the triplet system of neutral helium. LÄS MER

  4. 4. 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