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Functional simulator of the energetic electron detector from the TARANIS project
Enžl, Jakub ; Přech, Lubomír (advisor) ; Němeček, Zdeněk (referee)
Over a signi cant period of time there have been observations of storm-connected phenomena - so called Transient Luminous Events (TLE). In order to perform new measurements, a microsatellite is being developed under a project called TARANIS. The microsatellite is to carry a device designed to measure high-energy electrons IDEE. Its analyser developed at the Department of Surface and Plasma Science (Faculty of Mathematics and Physics, Charles University) should perform overall control of the detector and processing of registered data. The analyzer will also generate an Alert signal to inform other TARANIS devices whenever TLE-related event such as Relativistic Runaway Electon burst is observed. In order to test the analyzer an 4IDEE detector simulator is being developed. It's task is to generate data and send it to the analyzer. The data should be consistent with the ones expected to be measured during TLE. Another phenomenon to be studied by TARANIS is lightning-induced electron precipitation. Registration of such data will be simulated as well.
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Study of ionospheric F2 layer dynamics using Digisonde DPS-4 measurements in Pruhonice observatory
Kouba, Daniel ; Koucká Knížová, Petra (advisor) ; Ondrášková, Adriena (referee) ; Přech, Lubomír (referee)
Title: Ionospheric drift measurements Author: Daniel Kouba Department: Department of Surface and Plasma Science Supervisor: RNDr. Petra Koucká Knížová, Ph.D. Institute of Atmospheric Physics, Academy of Sciences of the Czech Republic Abstract: This thesis deals with ionospheric drift measurements using Digisonde DPS-4. The results are divided into theoretical and practical part. It is shown that for drift data processing it is necessary to choose correct reflection points corresponding to drift movements first. The selection is made in three steps: restriction of Doppler frequency shift, height range selection, choice of the maximum zenith angle. After- wards it is possible to credibly estimate the vector of drift velocity. The experimental results of drift measurements are based on data from the Pru- honice station. To study the common behavior of ionospheric drifts during quiet conditions, the statistical characteristics of drift velocity components are investiga- ted in layers E and F during geomagnetic quiet year 2006. The maximal daily amplitude of horizontal velocity demonstrates the influence of geomagnetic activity. It is proved to be considerable in the F layer meanwhile it was not observed in the E layer. The effect of strong geomagnetic disturbances is shown at two examples of extreme storms. The...
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Accuracy test of Earth's bow shock position models for subsolar and high-latitude observations of the INTERBALL-1, CLUSTER, and GEOTAIL spacecraft
Stránská Matějová, Jana ; Přech, Lubomír (advisor)
Title: Accuracy test of the Earth's bow shock position models for subsolar and high-latitude observations of the INTERBALL-1, CLUSTER and GEOTAIL spacecraft Author: Jana Matějová Department: Department of Surface and Plasma Science Supervisor: Doc. RNDr. Lubomír Přech, Dr. Supervisor's e-mail: lubomir.prech@mff.cuni.cz Abstract: In the presented study the relationship between the location of the Earth's bow shock and the solar wind parameters, the IMF magnitude and the tilt of the Earth's dipole is inves- tigated. Newly identified observations by INTERBALL-1 and CLUSTER satellites, which cover the frontal region of the shock including high latitudes, were added. Using the recently added observations a statistical comparison of the current bow shock models was carried out both ge- nerally and for particular regions. On the basis of the comparison a correction to the model ? has been drawn up. It comprises IMF magnitude and tilt angle influence and it is divided into three different surfaces. In spite of the lack of high-latitude data, the result of the extrapolation is a surface with expected indentations above the cusps. The accuracy of this correction has been compared with other models and the way how to join it to the only surface has been suggested. Keywords: Earth's bow shock, INTERBALL-1, CLUSTER,...
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Magnetic reconnection in the solar wind
Enžl, Jakub ; Přech, Lubomír (advisor)
Magnetic reconnection is a fundamental process that changes magnetic field configuration and converts a magnetic energy to flow energy and plasma heating. It can be found in a plasma with frozen magnetic field lines at boundaries where different magnetic field topologies encounter each other and thin current sheets are created as it is typical in the solar wind. In the thesis, we have used spacecraft measurements of solar wind plasma and magnetic field to found magnetic reconnection exhausts. We analyze and compare them with theoretical predictions. The results of the statistical analysis oriented on re-distribution of the magnetic energy in reconnection showed that both a portion of the energy deposited into heat as well as the energy spent on an acceleration of the exhaust plasma increase with the magnetic shear angle in accord with the increase of the magnetic flux available for reconnection. Moreover, we identify unusual events in the solar wind; we found magnetic reconnection exhausts accompanied by one or two side jets and explained their possible causes.
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