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?

2006-2008 radiation belt more robust in the absence of

sustained geomagnetic activity

Slot region widening in 2008-2009

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