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An investigation of the structure of rotational discontinuities
Author(s) -
Goodrich C. C.,
Cargill P. J.
Publication year - 1991
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/90gl02436
Subject(s) - classification of discontinuities , rotation (mathematics) , discontinuity (linguistics) , magnetic field , physics , field (mathematics) , upstream (networking) , magnetic structure , computational physics , magnetization , geometry , mathematics , mathematical analysis , quantum mechanics , computer network , computer science , pure mathematics
The structure of rotational discontinuities (RDs) has been studied through hybrid simulations for a range of propagation angle Θ bn between the discontinuity normal and the upstream magnetic field and plasma β. For sufficiently narrow initial states, the simulations produce quasi‐steady “reverse rotation” magnetic field structures for 30° ≤ Θ bn ≤ 60° and 0 < β ≤ 1 on a time scale of roughly 200 Ω i −1 . This structure is characterized by a right handed field rotation upstream joined smoothly to a left handed field rotation downstream; its width decreases from 60–70 c/ω pi at Θ bn = 30° to less than 25 c/ω pi at Θ bn = 60°. The magnetic field hodograms of our RD results have a distinctive S‐shape which is most pronounced in simulations with small Θ bn and initially right handed rotations. The reverse rotation structure is the net result of the expansion of the initial current layer via the fast and intermediate wave modes.