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| VOLUME 85 (2007) | ISSUE 5 | PAGE 288 |
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Strong space plasma magnetic barriers and Alfvénic collapse
E. A. Kuznetsov+*, S. P. Savin*, E. Amata
 , M. Dunlop , Y. Khotyaintsev∇, L. M. Zelenyi*, E. V. Panov , J. Büchner , S. A. Romanov*, J. Blecki°, J. L. Rauch , B. Nikutowski+L.D. Landau Institute for Theoretical Physics RAS, 119334 Moscow, Russia *Space Research Institute RAS, 117997 Moscow, Russia Istituto di Fisica dello Spazio Interplanetario, INAF, 00133 Roma, ItalySpace Science and Technology Department, Rutherford Appleton Laboratory, OX110QX Chilton, UK∇Swedish Institute of Space Physics, 75121 Uppsala, Sweden Max-Planck-Institut für Sonnensystemforschung, 37191 Katlenburg-Lindau, Germany°Space Research Center, Polish Academy of Sciences, Warsaw, 00716 Poland Laboratoire de Physique et Chimie, de l'Environnement, CNRS, Orléans, 45071 France
PACS: 52.30.-q, 52.40.Hf, 52.40.-w
Abstract
We propose to interpret high-magnitude magnetic barriers in space and solar plasma as due to pile-up of magnetic field lines and their Alfvénic collapse for MHD flows. The analysis of experimental data of both Interball and Cluster spacecrafts shows that high-magnitude magnetic structures found in the Earth magnetosheath and near the magnetopause are supported by a nearly thermal transverse plasma flow, with the minimum barrier width being of the order of the ion gyroradius. The collapse termination at such scales can be explained by the balance between pile-up of magnetic field lines and backward finite-gyroradius diffusion. Intercomparison of the theory, modeling and experimental data points out that the Alfvénic collapse is in general a promising mechanism for magnetic field generation and plasma separation. |