Institute of Geophysics of the CAS, v. v. i.

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Geomagnetism

Geomagnetic Department

The Department runs a geomagnetic observatory at Budkov (BDV, southern Bohemia). Origins of regular measurements of the Earths magnetic field are dated back to 1839. Since 1992, the observatory is digitized (a modification of the CANMOS system was installed in co-operation with the Geomagnetic Observatory of the Geological Survey of Canada) and in 1994 the observatory became part of the INTERMAGNET Network.

The Geomagnetic Department has been issuing daily forecasts of geomagnetic activity for Central Europe since 1994, weekly forecasts began in spring 1995. Since 1998 the short term forecasts have been sent to Czech TV. They are presented as part of the Weather Forecast and displayed on the teletext of Czech TV. At present, the forecasts, as well as reports of the actual state of the geomagnetic field in our region, are available on the web pages of the Regional Warning Centre Prague.

A group of researchers of the department is involved in numerical modelling of the geodynamo and participates in an INTAS Project 03-51-5807 “Long-time magnetohydrodynamics of the Earth, planets and moons”, in close cooperation with the Research Computing Centre of the Moscow State University. Furthermore, it participates in the COST724 Action “Developing the scientific basis for monitoring, modelling and predicting Space Weather”.

Finally, researchers of the department are involved in basic rock magnetic reasearch and its environmental applications, mainly focusing on the identification and magnetic characterization of different iron-bearing minerals occurring in various environments. An EU 5FP Project MAGPROX was completed in 2004. Within this Project, we collaborated with laboratories in Poland (Zabrze), Germany (Tuebingen) and Austria (Leoben). In addition to that, several bi-lateral cooperations contribute greatly to this research (e.g., Sofia, Bulg.aria; Dourbes, Belgium; Aix en Provence, France).

Head of the department: RNDr. Eduard Petrovský, CSc.

Previous Department of Geoelectricity

carries out research into the electrical conductivity distribution in the Earth's crust and upper mantle based on passive electromagnetic induction methods. For this purpose, we perform magnetotelluric field experiments in which time variations of the Earth's magnetic field and of its induced electric response are recorded within a broad frequency range, typically from 1 kHz down to few tenthousandths of Hz. By processing and analyzing those records, cross-sections of the electrical conductivity in the Earth can be derived, typically within the depth range from a few hundreds of meters down to several tens of km, and further interpreted in terms of the material composition, geological structures and physical state conditions of the Earth's interior. Geomagnetic depth soundings to great depths, as deep as 1000 km, are carried out by analyzing geomagnetic data provided by permanent observatories. As to the methodology, numerical simulation methods for the modelling of electromagnetic fields in a non-uniform and anisotropic Earth are studied and stochastic algorithms for magnetotelluric inverse solutions are developed.
 
The department further conducts research into selected topics of external geomagnetic fields, particularly the electromagnetic wave propagation in the Earth's ionosphere and magnetosphere and generation processes for geomagnetic pulsations, statistics of external geomagnetic phenomena and their relation to the interplanetary magnetic field, and specific problems of solar-terrestrial relations with special regard to the dynamics of the solar system.