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Non-Coherent Scattering in Stellar AtmospheresPowerPoint Presentation

Non-Coherent Scattering in Stellar Atmospheres

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Non-Coherent Scattering in Stellar Atmospheres

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Non-Coherent ScatteringinStellar Atmospheres

P. Heinzel

S=B

Special new problems

Absorption profile for a two-level atom known, f1=fM (Voigt fct)

For a three-level atom, transition 2 -> 3, NOT known since f2 will differ

from fM due to a selective absorption

Emission profile for transition 3 -> 2 also NOT known, f3 also differs from

fM

For CRD we have fi=fM

- Spontaneous emission
- Inellastic collisions
- Ionization and recombination
- Excitation by frequency-independent radiation
-> i *

Finite number of atomic levels -> finite number of non-Markovian radiation processes

1*=>2=>3 … =>n->I

GRF describe photon correlations in each sequence of

consecutive radiation transitions of the atom that starts from naturally populated initial level

- ->3*->1 prob{->3*}
- 1*=>3->1 prob{1*=>3}
- ->2*=>3->1 prob{->2*=>3}
- 1*=>2=>3->1 prob{1*=>2=>3}

- -> 2* => 3 prob{->2*}
- 1*=>2=>3 prob{1*=>2}

- Generalized redistribution functions
- Multilevel cases
- General approach
- Solution of the transfer problem
(2-level atom, ETLA, ETLA+LINEAR, MALI)

- Applications