Solar corona and wind

• Recording.
• PowerPoint presentation. In Czech only.
• PowerPoint presentation from the previous year (corresponds to the recording). In Czech only
• Hand-written notes.

• Solar corona is about 1 MK hot. It has many layers differing by the origin of light. Some of the light is the reflected light from the photosphere (F-corona, K-corona) on free electrons (Thompson scattering), some of the light is the own light of the coronal material (E-corona for the emission lines, T-corona for the thermal emission of the dust). Some of the emission lines may be the forbidden transitions observable also in the visible ranges of the electromagnetic spectrum.
• The diagnostics of the emission lines is a very well elaborated discipline of solar physics. Key terms: DEM = differential emission measure = amount of irratiang plasma as a function of temperature. It is averaged over the line of sight (in height). EM = emission measure = the total amount of irradiating plasma irrespectible of temperature. EM(T) = EM loci = amount of irradiating plasma as a function of temperature. The EM(T) curves allow the diagnostics of the multithermality of the plasma also in princple also allow to determine the abundances.
• Coronal heating is a unresolve issue. It is clear the it has to do with the processes in the magnetic field. Viable classes of processes are the reconnections (DC models) and waves (AC models).
• Solar wind is a continuous flow of charged particles from the Sun. It has two (three) components -- slow (400 km/s), fast (700 km/s), and explosive events (typically 1200 km/s). The slow component originates from the closed-field regions (active regions), the fast originates in the open-field regions (coronal holes).
• The solar wind dynamically forms the heliosphere. This is the sphere of the prevailing solar plasma, whereas outside the interstellar plasma dominates. It consists of super-sonic region in the inner Solar system, termination shock where the wind goes sub-sonic, the heliosheath of the turbulent wind and the magnetopause, where the dynamical (ram) pressure of the solar wind is ballanced by the pressure of the interstellar plasma. The heliopause is probably deformed by the proper motion of the solar system with respect to the interstellar background. The degree of deformation is currently being questioned.
• The interplanetary magnetic field (IMF) forms the balerina-skirt feature. When crossed by the plane of ecliptic, it shows a sectorial feature.