The expected imprint of flux rope geometry on suprathermal electrons in magnetic clouds

Owens, M. J. ORCID: https://orcid.org/0000-0003-2061-2453, Crooker, N.U. and Horbury, T.S. (2009) The expected imprint of flux rope geometry on suprathermal electrons in magnetic clouds. Annales Geophysicae, 27 (10). pp. 4057-4067. ISSN 0992-7689

Abstract/Summary

Magnetic clouds are a subset of interplanetary coronal mass ejections characterized by a smooth rotation in the magnetic field direction, which is interpreted as a signature of a magnetic flux rope. Suprathermal electron observations indicate that one or both ends of a magnetic cloud typically remain connected to the Sun as it moves out through the heliosphere. With distance from the axis of the flux rope, out toward its edge, the magnetic field winds more tightly about the axis and electrons must traverse longer magnetic field lines to reach the same heliocentric distance. This increased time of flight allows greater pitch-angle scattering to occur, meaning suprathermal electron pitch-angle distributions should be systematically broader at the edges of the flux rope than at the axis. We model this effect with an analytical magnetic flux rope model and a numerical scheme for suprathermal electron pitch-angle scattering and find that the signature of a magnetic flux rope should be observable with the typical pitch-angle resolution of suprathermal electron data provided ACE's SWEPAM instrument. Evidence of this signature in the observations, however, is weak, possibly because reconnection of magnetic fields within the flux rope acts to intermix flux tubes.

Item Type	Article
URI	https://reading-clone.eprints-hosting.org/id/eprint/5813
Refereed	Yes
Divisions	No Reading authors. Back catalogue items
Uncontrolled Keywords	Interplanetary physics; Interplanetary magnetic fields; Energetic particles; Solar physics, astrophysics, and astronomy; Flares and mass ejections
Publisher	Copernicus Publications
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