The Sun as a star. Solar instrumentation. Solar spectra. Theory of radiative transfer. Dynamical processes: dopplergrams, granulation, supergranulation, solar. Magnetic processes: solar cycle, magnetometers. Chromosphere and corona. Flares and CMEs. Space Weather.
Internal structure of the Sun.
Helioseismology. Solar dynamo. Magnetic structures models: sunspots, coronal loops and prominences. Coronal heating. Solar wind models. Heliosphere and its interaction with the interstellar medium.
E. Landi Degl'Innocenti: Fisica Solare, 2007, Springer Verlag
Learning Objectives
Knowledge acquired:
The Sun as a star and as an astrophysical laboratory. Physics underneath the processes that rule the Sun. Spectrum formation, dynamic Sun and role of magnetic fields.
The outer regions of the Sun.
Competence acquired :
Line formation in a stellar atmosphere from equilibrium to non-equilibrium.
Role of magnetic field in the solar atmosphere.
The solar cycle, different aspects of the same phenomenon.
Skills acquired (at the end of the course):
Solar observation interpretation (spectroscopy and photometry) from visible light to extreme ultraviolet.
Prerequisites
Basic courses in physics
Teaching Methods
6 CFU
Lectures hours: 48
Further information
Office hours
M. Romoli: by appointment
romoli@arcetri.astro.it
M. Velli: by appointment
velli@arcetri.astro.it
Website
Type of Assessment
Oral test
Alternatively to the standard oral test, the credit can be achieved through a oral seminar based on a subject agreed between the student and the teacher, consisting of reading and discussing a paper from literature.
Course program
Historical and phenomenological introduction.
The Sun through observations.
Ground-based observations: seeing, observing sites, solar telescopes with long and short focal length.
Focal plane instrumentation: grating spectroscopy, Lyot filter, Fabry-Perot filter.
The solar spectrum in photosphere.
Radiative transport equation: introduction, formal solution.
Stellar atmospheres: approximations, grey atmosphere, realistic models.
Lorentz electron theory: Thompson scattering, Rayleigh scattering,resonance, quantistic correction.
Line profiles: collisional, Doppler broadening.
Line spectrum: introduction on non-LTE models.
Solar dynamics. Doppler effect. Cinematical effects on velocity measurements. Dopplergram. Granulation. Mesogranulation. Supergranulation.
Magnetic field: MHD equations, Alfven theorem. Flux tubes, sunspots, pores, active regions. Solar activity cycle.
Zeeman effect: introduction, classical theoretical description. Basics of the quantum solution.
Outer layers of the solar atmosphere. The chromosphere: phenomena, physical and observative properties, magnetic field interactions.
Transition region: phenomena, ionization balance in non-ETL.
Prominences: phenomena, stability.
Solar corona: phenomena, visible light corona, EUV and X corona, spectral line formation, and spectroscopic diagnostics.
Flares. Magnetic origins of the solar corona, coronal heating and acceleration of the solar wind.