Executive summary

In recent years it has become more and more clear that perturbations of the magnetic environment of the Earth or the `Space Weather' can have an important influence on telecommunications and space-borne and ground-based technological systems. The drivers of Space Weather perturbations are of solar origin, namely transient phenomena -- of which coronal mass ejections (CMEs) are the most prominent -- superposed on the background solar wind. However, the basic physical mechanisms of solar origin which determine Space Weather are not well understood. As a result, presently used schemes for Space Weather predictions are rather `empirical' and not very successful: two out of three predictions turn out to be wrong!

The purpose of the present project is to study the physics behind the recurrent structure, heating and acceleration of the solar wind, the acceleration of energetic particles, and the formation and propagation of transients like CMEs and induced shocks from their birth in the solar corona up to their arrival at the Earth's magnetosphere. These aspects of Space Weather will be studied theoretically by various means, including global numerical simulations using the three-dimensional magnetohydrodynamics (MHD) equations on massively parallel computers, and observationally by means of thorough analysis and interpretation of a wide range of observational data gathered by ground observations and satellites, including SOHO, ULYSSES, ACE and Cluster II. The predictive capabilities of such global MHD simulation models will be evaluated and discrepancies will be identified. Hence, the cross-fertilization between theory and observation is of crucial importance for understanding the basic physical processes that determine Space Weather.

Nine `small' research teams from 5 different European countries will collaborate in this effort (see Sect. 3 for a short description of these teams and their role in the project). These groups have different but complementary expertise and each play a leading role in their major discipline. As a result, the combined expertise covers theoretical modeling (CMEs, solar wind, shock waves, etc.) and observational (EIT, LASCO, radio observations) solar physics, aeronomy and magnetospheric physics (ULYSSES), numerical techniques, large-scale computer simulations and numerical analysis. This well-considered and carefully balanced combination is of vital importance for the success of the project. As a matter of fact, the objectives (see Sect. 2.1) of the present project require an intensive collaboration of these groups in order to build a (European) team that is stronger than the sum of its components. This combined effort will hopefully lead to a breakthrough in our insight in the solar driving mechanisms of Space Weather. The proposed research will provide a basic understanding of important physical processes, and global simulation techniques will be developed which may become useful for more reliable science-based Space Weather predictions.

This project proposal is particularly timely because SOHO is currently gathering data of CMEs with unprecedented resolution in space and time and Cluster II will be operational (simultaneously with SOHO) at the end of this year. As a matter of fact, European initiatives, such as SOHO and ULYSSES, have put Europe in an ideal position to catch up with the USA on Space Weather expertise (see Sect. 2.2 for a concise description of the present situation). However, this requires immediate action. Especially if we want to take full advantage of NASA initiatives like STEREO (with an open data policy).


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David Berghmans
2000-09-18