Energy balance and temperature structure in solar prominences
| Název práce v češtině: | Energetická rovnováha a teplotní struktura ve slunečních protuberancích |
|---|---|
| Název v anglickém jazyce: | Energy balance and temperature structure in solar prominences |
| Klíčová slova: | Slunce -|Protuberance|Plazma|Záření |
| Klíčová slova anglicky: | Sun|Prominences|Plasma|Radiation |
| Akademický rok vypsání: | 2020/2021 |
| Typ práce: | diplomová práce |
| Jazyk práce: | angličtina |
| Ústav: | Ústav teoretické fyziky (32-UTF) |
| Vedoucí / školitel: | prof. RNDr. Petr Heinzel, DrSc. |
| Řešitel: | Mgr. Dominik Beck - zadáno a potvrzeno stud. odd. |
| Datum přihlášení: | 06.02.2021 |
| Datum zadání: | 19.02.2021 |
| Datum potvrzení stud. oddělením: | 05.04.2021 |
| Datum a čas obhajoby: | 23.06.2021 10:30 |
| Datum odevzdání elektronické podoby: | 21.05.2021 |
| Datum odevzdání tištěné podoby: | 21.05.2021 |
| Datum proběhlé obhajoby: | 23.06.2021 |
| Oponenti: | doc. RNDr. Michal Varady, Ph.D. |
| Zásady pro vypracování |
| 1) Making a recherche of theoretical prominence models
2) Understanding individual mechanisms which can contribute to prominence energy balance 3) Formulating the problem of energy balance in terms of CL, writing linearized equations of radiative transfer, statistical equilibrium, pressure and energy balance, together with relevant boundary conditions 4) Writing a numerical code to solve the system of linearized equations (multi-dimensional Newton-Raphson method) 5) Computing a grid of various models 6) Comparing the results with previous studies and with available observations 7) Discussing the results |
| Seznam odborné literatury |
| Auer, L.H. and Mihalas, D. 1969, ApJ 158, 641
Soler, R. et al. 2015, ApJ 810, 146 Vial, J.C. and Engvold, O. (eds.) 2015, Solar Prominences, ASSL 415, Springer Fontenla, J. et al. 1996, ApJ 466, 496 Gunár, S. 2014, IAU Symposium 300 Heasley, J.N. and Mihalas, D. 1976, 205, 273 Heinzel, P. 2015, in Solar Prominences, eds. J.C. Vial and O. Engvold, Ch. 5 Heinzel, P. and Anzer, U. 2001, A&A 375, 1082 Heinzel, P., Vial, J.C., and Anzer, U. 2014, A&A 564, A132 Hubeny, I. and Mihalas, D. 2015, Theory of Stellar Atmospheres, Princeton Univ. Press |
| Předběžná náplň práce v anglickém jazyce |
| Solar prominences are cool (~10,000 K) plasma structures embedded inside the hot solar corona (~ 106 K). They are supported against the gravity by coronal magnetic fields which also insulate them from surrounding hot plasmas. So-called quiescent prominences are relatively stable over many days. However, they may erupt due to magnetic-field instabilities. Erupting prominences are often associated with huge ejections of the coronal material (Coronal Mass Ejections) which affects the heliosphere and our Earth – we call this “the space weather”.
Proposed master thesis would initially deal with quiescent prominences which are often modeled as 1D or 2D plasma slabs representing either the whole prominence or, better, its fine structures (Heinzel and Anzer 2001, Gunár 2014). It is of continuing interest to model the temperature structure of such slabs and to understand the role of various physical mechanisms in the heating and cooling of prominence plasma – the so-called energy balance. In the pioneering work of Heasley and Mihalas (1976) on this topic, a set of non-linear equations of radiative transfer and energy balance was solved by the method of complete linearization (CL) (see Auer and Mihalas 1969) originally developed for stellar atmospheres which are out of a Local Thermodynamic Equilibrium (the so-called non-LTE problem). In their work only the hydrogen and helium were considered. Recently, Heinzel et al. (2014) added also calcium and magnesium to account more consistently for plasma radiation losses in the energy equation. Together with detailed incident radiation illuminating prominences from the solar disk (and partially from the corona), the latter models provided the temperature structure of prominences assuming the radiation equilibrium. The aim of the proposed master thesis is to advance beyond the assumption of radiation equilibrium and consider other mechanisms of heating and cooling, namely the conduction, enthalpy, and ambipolar diffusion (AD). AD was already included in the modeling of Fontenla et al. (1995), but their results concerning the hydrogen Lyman lines, and namely Lyman-beta, were largely inconsistent with available observations. Since 1996, we have a large set of observed prominence spectra in Lyman lines from the SOHO satellite (SUMER spectrometer) and we will soon obtain new Lyman-beta observations from the spectrometer SPICE onboard recently launched Solar Orbiter - a European mission towards the Sun. With such a wealth of observations available, it is very timely to reconsider the problem of the role of AD in the energy balance of prominences. Moreover, AD is also important for the theoretical modeling of prominence oscillations and wave propagation, so-far done without a self-consistent treatment of the non-LTE radiative transfer and partial ionization of plasma (see Ballester, submitted to A&A). |