Multi-spacecraft observations of the magnetotail in the CLUSTER era; The 
telescope-microscope combination 

Baker, D.N., Blake, J.B., Burch, J.L., Donovan, E.F., Dunlop, M., Frey, H.U., 
Korth, A., Mende, S.B., Singer, H.J. 


The magnetospheric research community has long sought the capability to view the 
Sun-Earth system in a global way and concurrently to probe the microphysical 
details of key physical regions. This objective has now been substantially 
realized with the combination of the CLUSTER and IMAGE missions. With the 
addition of SOHO, ACE, FAST, SAMPEX, POLAR, and geostationary orbit spacecraft, 
there is a remarkable ability to apply both telescopic and microscopic 
principles. Several recent examples serve to illustrate the observational power 
of these new tools. In the case of 31 March 2001, we observed a major 
geomagnetic storm and saw a powerful compression of the magnetosphere and a 
concomitant strong substorm. This event showed a large energetic particle 
injection deep in the magnetosphere far toward the dusk sector. In another event 
on 27 August 2001, CLUSTER observed a clear substorm sequence of events in the 
mid-magnetotail region (X ~ 19 RE). In this case, evidence suggests that 
magnetic reconnection began on the closed field lines of the plasma sheet about 
seven minutes prior to the magnetic field dipolarization and current disruption 
seen at geostationary orbit and the auroral brightening seen in IMAGE global 
images. In these, and many other cases, CLUSTER data reveal microphysical 
details while IMAGE and other spacecraft show the global, macroscopic context. 
These new observations can lead to an unprecedented understanding of magnetotail 
dynamical processes.  

_______________
Presented at the 2002 Spring A.G.U. Meeting, 
Washington, D.C., U.S.A., 28-31 May 2002