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The influence of solar activity on failure rate of components of Czech power-distribution network
Výbošťoková, Tatiana ; Švanda, Michal (advisor) ; Mošna, Zbyšek (referee)
We analyse the impact of solar activity on Czech power grid. Massive solar flares are responsible for the formation of spaceweather and have a certain impact on technological infrastructures on the Earth and in its surroundings. We elaborated this issue and studied possible effects of spaceweather events on failure rate recorded in Czech power grid. The basis of the practical part is a program that processes the data recording the disturbances on power grid in the Czech Republic obtained by ČEPS (Czech Transmission System Operator) and compared those with the measured values of geomagnetic activity from Budkov station in Šumava by the statistical analysis methods. Our study revealed that there possibly exists some connection between the intensity of solar activity and disturbances in the Czech eletrical power grid. It turns out that the number of faults on the grid during the period of increased solar activity is appreciably higher than in the period of lower solar activity. Our work contributes to the propagation of awareness of disturbances in the Czech electrical power grid that can also arise due to solar activity
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Flare stars
Kára, Jan ; Wolf, Marek (advisor) ; Švanda, Michal (referee)
The works deals with the study of the flare stars, which is a group of stars for which sudden brightening can be observed. The work focuses on a star GJ 3236, which is a low-mass eclipsing binary and on which numerous flares have been observed. For the analysis of this system spectroscopic and photometric data were used, which were obtained at various observatories. Parameters of the binary system have been determined by analysing spectroscopic and photometric data with the program PHOEBE. A total of 241 flares have been detected in the photometric data and for 190 flares, which light curves were not affected by eclipses, released energies were estimated. The set of flares was used for the study of stellar activity of the binary. The energy distribution of observed flares is similar to the flares observed on other flare stars and also on the Sun. This suggests, that the flare mechanism is the same for these stars.
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Road safety inspection in the Zlin region
Holcová, Veronika ; Švanda, Michal (referee) ; Matuszková, Radka (advisor)
The topic of this Diploma's thesis is Road safety inspection in the Zlín region. To start off, I was given 14 dangerous locations in the region of Zlín by the Road Services of Kroměříž; 7 of them at crossroads and 7 outside of crossroads. Then I analysed accident risks and compared the locations among each other according to safety features. Based on the outcome of my analysis, then I chose 2 locations at crossroads and 2 outside of crossroads which I personally visited and conducted analysis on how safe they are. I uncovered potential risks which could lead to traffic accidents and suggested solutions that eliminate or minimise that risk.
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Study of white-light flares
Mravcová, Lucia ; Švanda, Michal (advisor) ; Heinzel, Petr (referee)
Solar flares are a relatively common and strong demonstration of the solar ac- tivity and are observable throughout the whole electromagnetic spectrum. Some- times, solar flares are also accompanied with an emission in white-light contin- uum, then we speak of white-light flares. The origin of white-light flares is not entirely understood up to this day. The detection of white-light flares can be difficult, therefore we developed a program for automatic detection of white-light flares in SDO/HMI observations. After that, we studied properties of the detected white-light flares. Our work implies that there are two types of white-light flares depending on an X-ray flux of a solar flare. The difference between these two groups can be caused by a different behaviour of the magnetic field in the neigh- bourhood of the detected white-light flares. Our discovery could help in a better understanding of the origin of white-light flares. 1
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The dynamical disconnection of sunspots from their magnetic roots
Bárta, Tomáš ; Švanda, Michal (advisor) ; Sobotka, Michal (referee)
The thesis tries to verify a model for dynamic disconnection of sunspots from their magnetic roots proposed in the publication "The dynamical dis- connection of sunspots from their magnetic roots"(Schüssler & Rempel, 2005, Astron. Astrophys. 441, 337). In order to accomplish this task I conducted a numerical simulation, including a computation of a quiet Sun model using the OPAL opacity and equation of state tables. While simulating the time evolution of sunspot we retained the steps as are in the reffered article. The quiet Sun model corresponded well with other quiet Sun models, which are considered to be state-of-the-art. However, I was not able to reproduce the results fully as I didn't observe the dynamic disconnection. I suggest a more thorough testing of the presented code. 1
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Spectral continua and lines of hydrogen in solar flares
Procházka, Ondřej ; Kotrč, Pavel (advisor) ; Švanda, Michal (referee)
We present a unique design of a post-focal instrument suitable to detect fast changes of flux in waveband 350 - 440 nm. As it is not possible to measure the Sun as a star because of a strong background radiation in this waveband and using a thin slit makes it impossible to measure the whole flaring area we made a set of circular diaphragms of different sizes able to collect light only from a limited part of the Sun's atmosphere. For our data we also evolved new software technique based on statistical methods that even more increases a sensitivity on any changes in spectra. First results of observations of three X-class solar flares obtained in June 2014 proved significant increase of flux in Balmer continuum. One of these flares was measured from 20 minutes before a peak in SXR (GOES) so we were able to compare a whole impulsive phase with a state with no signs of a flare before it. Data suggest a radiation at Balmer limit (364,5 nm) of up to 5,5 stronger from flaring kernels compared to the quiet Sun. Powered by TCPDF (www.tcpdf.org)
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Zkušenosti s používáním metody local correlation tracking při studiu velkorozměrových rychlostních polí
Švanda, Michal ; Sobotka, Michal ; Klvaňa, Miroslav
We verify the reliability of the method recently used for the calculation of the large-scale velocity fields on synthetic dopplergrams obtained by a very simple numerical simulation of the supergranular pattern. A series of synthetic dopplergrams was stretched by the known vector field and the LCT was applied. The results were compared with the original vector field. Applying the LCT method on synthetic data we got an important experience in the behaviour of this method when used on full-disc dopplergrams. On the basis of the described tests we assume that the use of LCT on full-disc dopplergrams provides sufficiently reliable results, so that method could be used for mapping the large-scale velocities with resolution 60" and an accuracy 10 m/s.
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