General Findings Concerning the Magnetospheric Realm ILWS - 11 Science Workshop, Beijing, China, Aug-Sep 2011

Some Questions Addressed  What is a substorm ? A global process by which the magnetosphere unloads stored energy, supplied by the solar wind  However : pseudo-break-ups, isolated flow bursts…

 “In - Out” versus “Out - In” scenario Old controversy For each scenario there is a story connecting an instability (tail) evolution to that of the aurora THEMIS contribution; both scenarios observed => probably more than one physical mechanisms  Magnetosphere to Ionosphere mapping

 What are the precursors? Role of auroral streamers as onset precursors  What is the instability that triggers the substorm onset? Reconnection? NENL? Current Disruption? Ballooning?  How does a substorm fit within the larger system dynamics?

 Where are the “big” substorms? Are substorms occurring during different phases of the Solar Cycle so different?  What is the magnetospheric response to the unusual recent solar minimum? What is the radiation belts response? radiation belt more robust in the absence of sustained geomagnetic activity Slot region widening in

 What is the inner magnetosphere response during storms and substorms? The main phase ring current system (“Region-2”) is highly asymmetric and is driven by the pressure of the inner magnetosphere.

 How is plasma transported in the magnetosphere? How is it accelerated? What is the role of the O + ions outflow?

Lessons learnt and What do we need to better understand the magnetospheric dynamics?  Coordinated measurements have revolutionised substorm studies  Global magnetospheric and auroral imaging and multi-probes (accurate in-situ measurements) are proven critical tools  Importance of ground observations, coordinated with space missions  Small and large scale processes, cross-scale coupling (THEMIS, progression from Cluster-Double Star to MMS)  Simultaneous and continuous solar and solar wind monitoring necessary  Simulation and modelling

What do we need to better understand the magnetospheric dynamics? Missing strategic link: dedicated line of missions for simultaneous, coordinated in-situ measurements and global observations Need to cover :  the outer magnetosphere  the inner magnetosphere (ring current, radiation belts, plasmasphere)  the auroral region