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Liquid electrolytes with lower flammability
Hanzelka, Miroslav ; Vondrák, Jiří (referee) ; Sedlaříková, Marie (advisor)
The Bachelor’s thesis on subject Liquid electrolytes with lower flammability discusses about selection appropriate composition of electrolyte with consideration of higher safety for use in lithium-ion rechargeable batteries. The main objective of this work is to find that appropriate composition and find mutual relations between measurements.
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Nonlinear processes in space plasmas and their effects on the generation and propagation of electromagnetic waves
Hanzelka, Miroslav ; Santolík, Ondřej (advisor) ; Hellinger, Petr (referee) ; Rycroft, Michael J. (referee)
Nonlinear interactions of charged particles and large-amplitude waves have a signif- icant impact on magnetospheric dynamics. Here we focus on the cyclotron resonant interaction between energetic electrons and the discrete, whistler-mode chorus emissions in the Earth's outer radiation belt. The subject is introduced by an extensive review of whistler-mode dispersion properties, resonant electron trajectories and nonlinear wave- growth theories. We then present a new semi-empirical model of rising-tone chorus emis- sions with a fine subpacket structure. The model is then used in test-particle simulations to investigate nonlinear perturbations in hot electron distributions. Based on changes in electron fluxes, we estimate the resolution of spacecraft particle detectors required to detect the predicted perturbations. The test-particle method is further used to sim- ulate atmospheric precipitation of electrons caused by interaction with a single chorus wavepacket, and the result is put into connection with microbursts and pulsating auro- ras. We also detected a violation of the strong diffusion limit by the cyclotron resonant interaction, resulting in loss cone overfilling. 1
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Simulations of spacecraft measurements of electromagnetic waves in the Earth's magnetosphere
Hanzelka, Miroslav ; Santolík, Ondřej (advisor) ; Kolmašová, Ivana (referee)
For more than fifty years simulations of electromagnetic (EM) wave propa- gation are used to study the Earth's magnetosphere and to analyze EM emissions observed by spacecraft. In this work we focus on the propagation of EM waves in the frequency range from 100 Hz to 10 000 Hz within the region of the inner magnetosphere. We use a numerical procedure which performs ray tracing simu- lations and finds the wave trajectory along with other wave properties. Using these simulations we study propagation properties of equatorial noise emissions. Another subject of this work is development of a propagation scheme explaining a conjugate observation of quasiperiodic emissions by the Van Allen Probe A (VAP-A) spacecraft and the ground station in Athabasca. In this case we make use of a density distribution model based on measurements of plasmaspheric electron density done by the EMFISIS instrument onboard VAP-A. 1
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Ray tracing simulations of wave propagation in planetary magnetospheres
Hanzelka, Miroslav ; Santolík, Ondřej (advisor) ; Chum, Jaroslav (referee)
Electromagnetic (EM) waves in plasma influence the dynamics of plane- tary magnetospheres and affect the cosmic environment in orbital regions of man-made satellites. In this thesis, we present space physics applications of the ray tracing method as a tool for studying the propagation of plasma waves in the approximation of geometrical optics. Based on a simulation in cold plasma approximation we explain observed and unexpected changes in the wave vector direction of quasiperiodic waves measured by the low-orbit satellite DEMETER. We also studied, with the use of a hot plasma ray tra- cing code developed as a part of this thesis, the behavior of chorus emissions in the Earth's outer magnetosphere, focusing on the possible ducting of these whistler mode waves and the evolution of wave magnetic energy. We show that large portion of chorus emissions observed by the Cluster spacecraft must be ducted and conclude that while the linear theory cannot fully ex- plain observed wave growth, it can make up a large portion of the observed increase in energy in the low and mid-latitudinal regions. Lastly, we present propagation characteristics of EM proton cyclotron waves in the water-ion rich magnetosphere of Saturn and we show that in contrast to observations in the Earth's magnetosphere, a direct observation of...
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Simulations of spacecraft measurements of electromagnetic waves in the Earth's magnetosphere
Hanzelka, Miroslav ; Santolík, Ondřej (advisor) ; Kolmašová, Ivana (referee)
For more than fifty years simulations of electromagnetic (EM) wave propa- gation are used to study the Earth's magnetosphere and to analyze EM emissions observed by spacecraft. In this work we focus on the propagation of EM waves in the frequency range from 100 Hz to 10 000 Hz within the region of the inner magnetosphere. We use a numerical procedure which performs ray tracing simu- lations and finds the wave trajectory along with other wave properties. Using these simulations we study propagation properties of equatorial noise emissions. Another subject of this work is development of a propagation scheme explaining a conjugate observation of quasiperiodic emissions by the Van Allen Probe A (VAP-A) spacecraft and the ground station in Athabasca. In this case we make use of a density distribution model based on measurements of plasmaspheric electron density done by the EMFISIS instrument onboard VAP-A. 1
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Liquid electrolytes with lower flammability
Hanzelka, Miroslav ; Vondrák, Jiří (referee) ; Sedlaříková, Marie (advisor)
The Bachelor’s thesis on subject Liquid electrolytes with lower flammability discusses about selection appropriate composition of electrolyte with consideration of higher safety for use in lithium-ion rechargeable batteries. The main objective of this work is to find that appropriate composition and find mutual relations between measurements.
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