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The nonlinear effects in the ionospheric plasma generated by strong thunderstorms seen by DEMETER satellite

Błęcki J., Wronowski R., Jujeczko P.

Archives of Mechanics

2024

Vol. 76, nr 3

277--290

The terrestrial ionosphere is mainly a plasma region which is very sensitive to different disturbances. A wide range of plasma instabilities can develop in this region, which are often nonlinear processes and leading to the development of plasma turbulence. Turbulence plays a crucial role in the dynamics of the space plasma processes. The turbulence appears when some physical parameter exceeds a certain level. It can have place during strong thunderstorms. The ionosphere is sometimes treated as plasma physics laboratory with unique possibility to study fundamental plasma processes. The use of ionospheric satellite gives the chance to perform insitu measurements of plasma parameters during dynamic processes. For our analysis we used a set of selected data of the electric and magnetic fields variations in ELF (Extra Low Frequency 10–1250 Hz) and VLF (Very Low Frequency 100–20000 Hz) ranges originated from the French microsatellite DEMETER which was operating on the circular orbit with inclination of about 80◦ at altitude of 660km from July 2004 until December 2010. The Fourier, wavelet and bispectral analyses of these signals are given in this paper. Three wave processes have been identified during few very strong strokes. In some cases the nonlinear interactions of whistlers with the VLF signals of ground based transmitters have been registered. The character of spectra suggests the presence of Richardson’s cascade. Our conclusion is that in few cases these results are related to whistler turbulence.

Geodynamic research at the Department of Planetary Geodesy, SRC PAS

Brzeziński A., Jóźwik M., Kaczorowski M., Kalarus M., Kasza D., Kosek W., Nastula J., Szczerbowski Z., Wińska M., Wronowski R., Zdunek R., Zieliński J. B.

Reports on Geodesy and Geoinformatics

2016

Vol. 100

131--147

The Department of Planetary Geodesy of the Space Research Centre PAS has been conducting research on a broad spectrum of problems within a field of global dynamics of the Earth. In this report we describe the investigations on selected subjects concerning polar motion (modeling and geophysical interpretation of the Chandler wobble, hydrological excitation of seasonal signals, search for optimal prediction methods), tectonic activity in the region of the Książ Geodynamic Laboratory of the SRC, and finally the new joint Polish-Italian project GalAc analyzing feasibility and usefulness of equipping second-generation Galileo satellites with accelerometers.

Nonlinear plasma wave processes observed in the polar cusp

Błęcki J., Wronowski R., Parrot M., Savin S.P.

Acta Geophysica

2007

Vol. 55, no. 4

459-468

We present observations of electric and magnetic field variations from proton (about few Hz) to electron cyclotron frequencies (about few kHz) obtained by STAFF instrument on Cluster satellites during two cusp crossings, at ~6 RE altitude, in September 2002. The cusp was identified by the presence of intensive fluxes of counter streaming electrons with low energies and broadband wave activity which is typical for this region. Special attention is given for the interval of measurements when the wave-form of the magnetic field fluctuations was taken in this region by CLUSTER satellites. The wave has been processed using the wavelet and bispectral analysis. Results showing the cascade of turbulence and wave-wave interactions are presented in this paper. A three wave process can be responsible for the broadening of the wave spectra in the polar cusp.