Short description
(English)
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By using the GEANT4 MAGNETOCOSMICS and ATMOCOSMICS codes that simulate the interaction of energetic particles with the Earth's magnetosphere and atmosphere, we will develop a tool that allows computing the ionisation of the atmosphere by cosmic rays. This tool will be used to study the variation of the atmosphere ionisation rate in function of solar activity, geomagnetic activity, during solar proton events and during Forbush decreases.
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Partners and International Organizations
(English)
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AT, BE, BG, CH, CZ, DE, DK, ES, FI, FR, GR, HU, IE, IL, IT, NO, PL, RO, RS, SE, SI, SK, TR, UK
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Abstract
(English)
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Cosmic rays are the primary source of the ionisation that takes place in the Earth's atmosphere below ~40 km altitude. This ionisation has an important impact on the chemistry and physics of the atmosphere and is currently discussed as a possible key factor in weather and climate processes. During this project we have developed a computer code that allows to evaluate the ionisation in the Earth's atmosphere in function of geographic position, altitude, time, geomagnetic activity, and solar activity. The code has been validated against experimental data during the first year of the project. In the second year of the project the major part of our work has been concentrated on the use of our code to model the ionisation of the Earth's atmosphere during solar energetic particle events. Our computations have shown e.g. that during the very powerful solar particle event of January 20, 2005, the high anisotropy and high intensity of the solar particle flux near Earth led to an extreme ionisation of the atmosphere in very concentrated areas in the polar regions. For this particular event we have also studied the influence of different magnetic field models on the results of our computations. In addition we have continued our collaborative work with EAWAG, the Swiss Federal Institute of Aquatic Science and Technology, consisting in the investigation of possible correlations between the decrease of the atmospheric ionisation and the variation of the cloud cover during short-time decreases in the cosmic ray intensity, i.e during so called Forbush decreases. Our work contributed substantially to the final COST-724 report (see COST724 website), and it will provide the basis for a major space weather application within the approved FP-7 program NMDB ('Real-time database for high resolution Neutron Monitor measurements'; Grant Agreement Number 213007).
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