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Whistler waves observed by the DEMETER spacecraft
Záhlava, Jan ; Němec, František (advisor) ; Macúšová, Eva (referee)
Although lightning-generated whistlers have been studied for nearly a century, there are still questions to be answered. It is clear that, at least in a certain frequency range, these waves significantly contribute to the overall wave intensity in the inner magnetosphere. They also influence distribution functions of energetic particles in the Van Allen radiation belts. Thanks to the on-board implemented neural network for automated whistler detection, we can relate electromagnetic wave and energetic particle flux measurements performed by the low-altitude DEMETER spacecraft with the number and dispersion of whistlers detected during a certain time interval. We distinguish the cases with high and low whistler occurrence and we use this information to determine the overall effect of lightning-generated whistlers. Powered by TCPDF (www.tcpdf.org)
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Electromagnetic whistler-mode waves in the plasma environment of the Earth's magnetosphere
Macúšová, Eva
Title: Electromagnetic whistler-mode waves in the plasma environment of the Earth's magne- tosphere. Author: Eva Macúšová Department: Department of Surface and Plasma Science Supervisor: Doc. RNDr. Ondřej Santolík, Dr., KFPP Abstract: Results of this doctoral thesis are based on observations provided by the Cluster and Double Star missions. We have determined the variability of the spatio-temporal characte- ristics of chorus-like emissions under dierent geomagnetic conditions from a data set covering almost four years of measurements provided by the equatorial Double Star TC-1 spacecraft. From the TC-1 data set we have also identied the dependence of frequency bandwidths, am- plitudes and occurrence rates of chorus-like emissions on the geomagnetic activity. We have also processed a similar data set from 11 years of Cluster measurements of electric and magnetic elds. This study was focussed on details of the spectral structure of individual chorus wave packets. We have used measurements from the WBD (Wideband) instrument situated onboard all four Cluster spacecraft. We have classied all types of spectral shapes and determined their occurrence rates. We have examined the dependence of chorus frequency drift rate df/dt on the cold plasma density ne and on the dimensionless parameter Q for several selected...
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Whistler waves observed by the DEMETER spacecraft
Záhlava, Jan ; Němec, František (advisor) ; Macúšová, Eva (referee)
Although lightning-generated whistlers have been studied for nearly a century, there are still questions to be answered. It is clear that, at least in a certain frequency range, these waves significantly contribute to the overall wave intensity in the inner magnetosphere. They also influence distribution functions of energetic particles in the Van Allen radiation belts. Thanks to the on-board implemented neural network for automated whistler detection, we can relate electromagnetic wave and energetic particle flux measurements performed by the low-altitude DEMETER spacecraft with the number and dispersion of whistlers detected during a certain time interval. We distinguish the cases with high and low whistler occurrence and we use this information to determine the overall effect of lightning-generated whistlers. Powered by TCPDF (www.tcpdf.org)
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