Stuttgart 2012 – scientific programme

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P: Fachverband Plasmaphysik

P 22: Poster: Sonstiges

P 22.1: Poster

Thursday, March 15, 2012, 16:30–19:00, Poster.III

The influence of lightnings on VLF/LF signals observed by radiophysical stations — •Bo Ram Lee, Claudia-Veronika Meister, Christoph Maurer, and Dieter H.H. Hoffmann — Institut für Kernphysik, TU Darmstadt, Schlossgartenstraße 9, 64289 Darmstadt, Germany

The theory of cosmic-ray shower-runaway breakdown in thunderclouds predicted by Gurevich et al. (Gurevich, Milikh, Roussel-Dupre, Phys. Lett. A 165, 463, 1992) is reviewed, and estimates of the electrical conductivity and electric fields during the electron avalanche are estimated. It is shown that the critical electric field amounts to a few 100 kV/m, which is below the usual atmospheric breakdown values. With the onset of the breakdown lightnings occur, which may be connected with the generation of radio pulses with frequencies of a few MHz. Besides also lower-frequency waves in the VLF region are excited. An overview on such waves is given. It is shown that lightnings influence the signals received by the TU Darmstadt VLF/LF radiophysical station VADAR constructed to detect possible earthquake precursors in Europe.