Radiodetektion von Luftschauern unter dem Einfluss starker elektrischer Felder in der Atmosphäre

Abstract

Radio detection of extensive air showers is a technique for measuring high energy cosmic ray particles which again has become a very active field of research over the last few years, driven by the availability of modern digital electronics. This detection method is based on radio emission caused by the geosynchrotron effect and has the advantage of a very high duty cycle of nearly 24 hours a day. However, it has been found that strong electric fields, as those occurring during thunderstorms, can influence the air shower radio signal. The influence of these atmospheric electric fields has been studied in this diploma thesis, based on the data of the LOPES experiment. Additionally, the air shower parameters reconstructed by the KASCADE-Grande experiment and measurements of the static electric field have been used. The influence of strong electric fields on the air shower signal has been shown to be significant, based on single events and on the entirety of all events that have been recorded during thunderstorms. It seems that even in absence of thunderstorms strong electric fields can influence the air shower signal. Furthermore, the additional background signals produced by atmospheric electricity during thunderstorms have been studied. It could be shown that these signals can also compromise the analysis of the recorded data. Thus, they are an additional source of errors in the reconstruction of air shower parameters on the basis of radio signals. During the development of a cosmic ray air shower the electric conditions in the atmosphere change. There are indications for a correlation between extensive air showers and the formation of lightnings. Within the experimental possibilities of the LOPES experiment this issue has also been investigated. The attempt to observe an air shower and a signal from lightning simultaneously has been made. No indications have been found that could support or disprove this theory. It can be assumed that this is due to the inability of the experimental design to address this particular question. Therefore, an experimental design suited to examine correlations between extensive air showers and lightnings has been proposed.