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non-LTE ゼミ 論文紹介「 The formation of the Hα line in the solar chromosphere 」 ①. 20120307 T . Anan. abstruct. Radiation-MHD simulation + 3D non-LTE radiative transfer computation => H α Statistical equilibrium Complete frequency redistribution Non-equilibrium ionization of hydrogen
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non-LTEゼミ論文紹介「The formation of the Hα line in the solar chromosphere」① 20120307 T. Anan
abstruct • Radiation-MHD simulation + 3D non-LTE radiative transfer computation => Hα • Statistical equilibrium • Complete frequency redistribution • Non-equilibrium ionization of hydrogen • We find • 3D radiative transfer is essential in modeling Hα • Hα opacity is mainly sensitive mass density • Hα core intensity is correlated with the average formation height • The line-core width is a measure of the gas temperature • Fibril-like structure • Formation height • Simulated results are very similar to observed one without the need for additional microturbilance
RADYN code • Hydrodynamics • Carlsson & Stein 1992, 1995, 1997, & 2002 • Eq. of conservation of mass, momentum, and energy • Non-LTE radiative transfer problem including non-equilibrium rate equations • Ionization balance • Equation of state • Partial redistribution of photons in the Ryman lines • Elements & levels • H I (5 levels + continuum) • Ca II (5 levels + continuum) • He I (5 levels + continuum) • He II (3 levels + continuum) • He III (1 levels + continuum) • Lower boundary is just below the photosphere (τ500nm = 16) • Velocity field derived from MDI (Doppler shift, 676.78 nm, Ni I, quiet region) • Upper boundary is corona at 10000 km above the lower boundary • Run for more than 1 hour of solar time, and saved output at 10 s intervals => 374 sapshots