On the association between energy conversion regions and high speed
flows in the plasma sheet

Octav Marghitu (1), Maria Hamrin (2), Patrik Norqvist (2), Berndt Klecker (3)

(1) Institute for Space Sciences, Bucharest, Romania
(2) Department of Physics, Umea University, Sweden
(3) Max Planck Institute for Extraterrestrial Physics, Garching, Germany

High speed flows are frequently observed in the plasma sheet,
providing a significant fraction of the mass, energy, and magnetic
flux transport in the coupled magnetosphere--ionosphere
system. Numerous studies over the last 20 years showed that much of
this transport takes place in the central plasma sheet, by the
so-called bursty bulk flows, known also as plasma bubbles. More
recently, the Cluster mission allowed a systematic investigation of
energy conversion regions (ECRs), identified as concentrated load
regions (CLRs, E.J>0, with E the electric field and J the current
density) and concentrated generator regions (CGRs, E.J<0). The ECRs
were often found to be associated with high speed flows both in the
central plasma sheet, where plasma velocity is mainly perpendicular to
the magnetic field, and in the plasma sheet boundary layer, where
plasma velocity is mainly parallel to the magnetic field. We present
some features of this association, as observed in both regions, and
discuss the similarities and differences between CLRs and CGRs. We
also compare the findings with recent data analysis and modeling
results.