Current structure and nonideal behavior at magnetic null points in the turbulent magnetosheath. Issue 4 (25th April 2013)

• Record Type: Journal Article
• Authors: Wendel, D. E.; Adrian, M. L.
• Is Part Of: Journal of geophysical research. Volume 118:Issue 4(2013:Apr.)
• Page Start: 1571
• Page End: 1588
• Publication Date: 2013-04-25
• Subjects: turbulence -- magnetosheath -- magnetic reconnection -- magnetic null points; Magnetospheric physics -- Periodicals; Space environment -- Periodicals; Cosmic physics -- Periodicals; Planets -- Atmospheres -- Periodicals; Heliosphere (Astrophysics) -- Periodicals; Geophysics -- Periodicals; 523.01
• DOI: 10.1002/jgra.50234
• Languages: English
• ISSNs: 2169-9380

Abstract

Abstract : [1] The Poincaré index indicates that the Cluster spacecraft tetrahedron entraps a number of 3‐D magnetic nulls during an encounter with the turbulent magnetosheath. Previous researchers have found evidence for reconnection at one of the many filamentary current layers observed by Cluster in this region. We find that many of the entrained nulls are also associated with strong currents. We dissect the current structure of a pair of spiral nulls that may be topologically connected. At both nulls, we find a strong current along the spine, accompanied by a somewhat more modest current perpendicular to the spine that tilts the fan toward the axis of the spine. The current along the fan is comparable to the that along the spine. At least one of the nulls manifests a rotational flow pattern in the fan plane that is consistent with torsional spine reconnection as predicted by theory. These results emphasize the importance of examining the magnetic topology in interpreting the nature of currents and reconnection in 3‐D turbulence. Key Points: Cluster finds nulls in turbulent magnetosheath associated with reconnection Multi‐point methods reveal importance of 3D topology of magnetic fields. We find plasma flows consistent with null‐point reconnection predicted by theory