### Syllabus of lectures

A brief review of solar and stellar spectroscopy.

Basics of radiative transfer: absorption and emission of radiation,
source function, optical depth, radiative-transfer equation, simple
illustrative solutions, Eddington-Barbier relation.

Two-level atom: basic processes, statistical equilibrium, LTE versus
non-LTE, solutions for semi-infinite atmosphere, basic properties
(thermalization of radiation).

Numerical solutions of the radiative-transfer equation coupled to
statistical equilibrium: Feautrier method, iterative methods (ALI,
MALI).

Multilevel atoms: general kinetic equilibrium, radiative and
collisional rates, ionization/ recombination processes, Milne-Einstein
relations for continuum, radiation losses.

Spectral line broadening, scattering of line radiation, partial redistribution.

Line formation in solar and stellar atmospheres, source-function variations, emergent line
shapes (lines in absorption/emission, line reversals, line asymmetries due to flows),
optically-thin UV lines (CHIANTI code), synthetic radio spectra in the ALMA range.

Basic equations of solar and stellar atmospheric modeling (hydrostatic
equilibrium, radiative equilibrium, non-LTE equations), illustrative
solutions for gray atmosphere, line blanketing.

Brief review of static and semi-empirical atmospheric models, solar
and stellar examples, modeling of solar/stellar flares and
prominences.

A review of numerical codes for atmospheric modeling, test-runs with the MALI code.

Basics of radiation-hydrodynamics (RHD), numerical RHD codes
(e.g. FLARIX, RADYN),example of time-dependent atmospheric modeling.