National Repository of Grey Literature 4 records found  Search took 0.00 seconds. 
Laboratory investigation of dust charging and impact ionization
Nouzák, Libor ; Pavlů, Jiří (advisor)
Dust is an almost ubiquitous component of the cosmic plasma (e.g., planetary and cometary magnetospheres, the heliosphere, the interstellar medium, supernova shells). However, it can be also frequently encountered in industrial applications as a principal agent in material treatments, or as an undesirable ingredient in a production of microelectronic components, or in fusion devices. Since dust particles are one of the main elements of interest in the solar system (e.g., Earth, Jovian and Saturnian systems) and in the interstellar medium, there is a number of missions (e.g., ROSETTA, Cassini) that provided investigations of the properties and global dynamics of charged dust grains. In these environments, the relevant charging processes are interactions with electrons and ions of the solar wind and photoemission by solar UV radiation that often dominates. However, in-site investigations of such processes are difficult because several processes act in accord. The present thesis studies charging processes in laboratory settings where these processes can be investigated separately. In the first series of experiments focused on applications in the lunar or planetary surroundings, a single (charged) dust grain is stored in an electrodynamic trap and expose to electron and/or ion beams with variable energies and...
Laboratory investigation of dust charging and impact ionization
Nouzák, Libor ; Pavlů, Jiří (advisor) ; Jeřáb, Martin (referee) ; Souček, Jan (referee)
Dust is an almost ubiquitous component of the cosmic plasma (e.g., planetary and cometary magnetospheres, the heliosphere, the interstellar medium, supernova shells). However, it can be also frequently encountered in industrial applications as a principal agent in material treatments, or as an undesirable ingredient in a production of microelectronic components, or in fusion devices. Since dust particles are one of the main elements of interest in the solar system (e.g., Earth, Jovian and Saturnian systems) and in the interstellar medium, there is a number of missions (e.g., ROSETTA, Cassini) that provided investigations of the properties and global dynamics of charged dust grains. In these environments, the relevant charging processes are interactions with electrons and ions of the solar wind and photoemission by solar UV radiation that often dominates. However, in-site investigations of such processes are difficult because several processes act in accord. The present thesis studies charging processes in laboratory settings where these processes can be investigated separately. In the first series of experiments focused on applications in the lunar or planetary surroundings, a single (charged) dust grain is stored in an electrodynamic trap and expose to electron and/or ion beams with variable energies and...
Dust-UV interaction
Nouzák, Libor ; Pavlů, Jiří (advisor) ; Žilavý, Peter (referee)
Title: Dust - UV interaction Author: Libor Nouzak Department: Department of Surface and Plasma Science Supervisor: RNDr. Jiri Pavlu, Ph.D. Supervisor's e-mail address: jiri.pavlu@mff.cuni.cz Abstract: Micrometer objects (dust grains) are an integral part of the universe. As other objects in the plasma, these dust grains charge to potencial close to the potencial of the plasmas (in this case, interplanetary plasma). In the universe, the photoelectric charging dust grain dominantes all other charging processes. In general, the resulting charge of dust grain is given by a balance of all processes, which haven't been mostly jet theoretically described. In our laboratory, we are simulating space conditions and measure resulting charge and his changes on a single separated dust grain. This work is partly focused to UV source application and to finishing its electronics, and partly on test measurements and model calculations, connected with newly built experiment (e.g., to estimate effects of backgound currents, surfaces, and the geometry of the dust trap electrodes). The work is finished by the first measurements of glass grain charge under electron bombardment with provisional detection optics. Obtained results are compared with previous measurements on the same type of dust grains. Key words: dust, dusty plasma,...

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