Advances in Understanding Elements of the Sun—Earth Links

Abstract

The study of the Sun–Earth connections is a science in full effervescence, as much as for the physical problems that arise as for its growing impact on our societies. This last case is illustrated by the emergence of a new field of research called Space Weather. The launch of this new concept (translated in French by météorologie de l’espace) deserves to be clarified in spite of a great number of articles and books devoted to this question. In this chapter we will not extensively describe what Space Weather is, but we will only emphasize some appropriate definitions and other main notions. We will first establish a clear distinction between Space Weather and Sun– Earth connections (and Space physics). In a next section, we will briefly review the Sun as a variable star (in the Space Weather context). Then we will underline the necessity to better predict solar cycles showing the physical difficulties for such an exercise, leading to the extreme complexity for forecasting specific events of high energy. We will succinctly describe the question of risks. At last we will conclude by giving some imprints for future works.