The Code COSI Code for Solar Irradiance

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The Code COSI Code for Solar Irradiance

• Presented by
• Margit Haberreiter
• PhD student at the
• PMOD/WRC
• and
• IfA, ETH Zurich

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Spherical symmetry
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Structure of COSI
atomic data energy levels, statistical weights,
transition probabilities
?
wrstart
set of population numbers (LTE)
?
wrcont
LTE
?
impact parameters are coupled
ray by ray solution for
?
non-LTE
como
?
moment transfer equation for
?
new radiation field J
?
steal
approximate lambda operators
?
statistical equations
?
until convergence
new set of population numbers
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Structure of COSI
converged population numbers
?
formal solution for all continuum and line
frequencies n and impact parameter pi known
source function
?
LTE
model
?
fioss8
calculation of emergent spectrum, flux profiles
of the lines
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Synthetic spectra for the quiet Sun
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What needs to be done

• Modification of the code COSI to account for
  solar radiative transport
• frequency grid, opacity sources (H minus, H, C,
  Al, Si, Mg, Fe)
• line levels, transition probabilities
• Validation of COSI
• by comparison with Kurucz ATLAS9
• by comparison with available data (SUMAR data)
• 3. non-LTE modeling
• modification of the code for non-LTE
• Model validation of the non-LTE model
• modeling the continuum and spectral lines
• wavelengths range around 215 and 265 nm, Lya

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Synthetic spectra for the quiet Sun