Header image  
 
 

Abstract

Flow-driven macroscopic instabilities play a major role in the dynamics of astrophysical systems such as stellar coronae, magnetospheric and heliospheric boundary layers, planetary magnetotails, cometary tails, and astrophysical jets. We propose a team of 12 people to identify and open new vistas for advancing the knowledge of flow-driven instabilities in space, solar and astrophysical plasma environments. In the past four years several new missions have been launched: Hinode, STEREO, THEMIS and SDO. The new, high-quality data from these missions combined with the matured analysis of data from earlier missions (Wind, SOHO, ACE, Cluster, TRACE and RHESSI) make it very timely to survey the breadth of observations showing evidence of flow-driven instabilities in solar and space plasma. These kinds of observations lead to measurements of very different and complementary parameters, e.g. the state of the local plasma in situ against the overall morphological features from remote observations. By combining observational and theoretical characterisations and by sensibly comparing solar and terrestrial phenomena, we plan to clarify and exploit similarities and, ultimately, gain a cross-fertilisation between the fields. The support from theory and numerical simulations is crucial for the creation of a unifying theory of wave-flow interactions in space plasmas and for understanding the role played by these phenomena in solar-terrestrial relations. The tasks of the team will be (1) to review flow-driven instabilities near the Earth, in the solar wind and in the solar corona, identifying the fundamental similarities, and (2) to carry out detailed specialised studies addressing the most pressing science questions, which include amongst others the mechanisms controlling boundary layer formation, the cascade of magnetohydrodynamic (MHD) waves into high frequency waves and post-eruptive wave phenomena. Our aim is to clarify the efficiency of the flow-driven instabilities in these processes, by comparing their role in the dynamics of various structures of the Sun-Earth system with recent and future observations of waves in flowing plasmas, as well as the use of plasma theory and numerical simulations. This requires direct comparisons of the onset conditions, as well as the spatial and temporal evolution characterisations of the waves occurring near flow-shear boundaries or driven by reconnection outflows.