Scales in a thinning plasma sheet
Petrukovich, A. A.; Balogh, A.; Nakamura, R.; Baumjohann, W.; Rème, H.; Runov, A.
Russia, Austria, United Kingdom, France
Abstract
With Cluster observations in the magnetotail, we study the dynamics of plasma sheet thinning and stretching in a typical growth phase event of September 12, 2001. The thinning and stretching proceed in parallel, with transient variations. The pre-onset value is Bz∼1.5 nT, J∼8 nA/m2. The current density increase is not accompanied with a corresponding number density increase. A large (>5 nT) guide field along the cross-tail current direction was registered. An embedded current sheet structure was detected and, therefore, caution is required if making thickness estimations.