Geophys. Res. Lett., 26, 1, 13-16, 1999
Abstract:
Planar magnetic structures are regions of solar wind plasma where the
magnetic field orientation is constrained within a fixed plane for
durations of several hours. Within these structures, magnetic field
discontinuities are seen, with the discontinuity surfaces being almost
co-planar. The results of a survey of planar magnetic strutures
detected by the Ulysses spacecraft are presented. When searching for
these events using minimum variance analysis, a large population was
detected of magnetic field structures whose directions described small
circles in the spacecraft's field of view (as opposed to great circles
described by "classic" planar magnetic structures). It is likely
that these "small-circle" events represents Alfvenic structures.
Variations in the nature of the structures at various heliographic
latitudes and differing solar wind conditions are
described. Implications of the results of the survey are discussed.
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