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| Titel |
Nonlinear Alfvén waves, discontinuities, proton perpendicular acceleration, and magnetic holes/decreases in interplanetary space and the magnetosphere: intermediate shocks? |
| VerfasserIn |
B. T. Tsurutani, G. S. Lakhina, J. S. Pickett, F. L. Guarnieri, N. Lin, B. E. Goldstein |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1023-5809
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| Digitales Dokument |
URL |
| Erschienen |
In: Nonlinear Processes in Geophysics ; 12, no. 3 ; Nr. 12, no. 3 (2005-02-18), S.321-336 |
| Datensatznummer |
250010588
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| Publikation (Nr.) |
 copernicus.org/npg-12-321-2005.pdf |
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| Zusammenfassung |
| Alfvén waves, discontinuities, proton perpendicular acceleration and
magnetic decreases (MDs) in interplanetary space are shown to be
interrelated. Discontinuities are the phase-steepened edges of Alfvén
waves. Magnetic decreases are caused by a diamagnetic effect from
perpendicularly accelerated (to the magnetic field) protons. The ion
acceleration is associated with the dissipation of phase-steepened
Alfvén waves, presumably through the Ponderomotive Force. Proton
perpendicular heating, through instabilities, lead to the generation of both
proton cyclotron waves and mirror mode structures. Electromagnetic and
electrostatic electron waves are detected as well. The Alfvén waves are
thus found to be both dispersive and dissipative, conditions indicting that
they may be intermediate shocks. The resultant "turbulence" created by the
Alfvén wave dissipation is quite complex. There are both propagating
(waves) and nonpropagating (mirror mode structures and MDs) byproducts.
Arguments are presented to indicate that similar processes associated with
Alfvén waves are occurring in the magnetosphere. In the magnetosphere,
the "turbulence" is even further complicated by the damping of obliquely
propagating proton cyclotron waves and the formation of electron holes, a
form of solitary waves. Interplanetary Alfvén waves are shown to rapidly
phase-steepen at a distance of 1AU from the Sun. A steepening rate of
~35 times per wavelength is indicated by Cluster-ACE measurements.
Interplanetary (reverse) shock compression of Alfvén waves is noted to
cause the rapid formation of MDs on the sunward side of corotating
interaction regions (CIRs). Although much has been learned about the
Alfvén wave phase-steepening processfrom space plasma observations, many
facets are still not understood. Several of these topics are discussed for
the interested researcher. Computer simulations and theoretical developments
will be particularly useful in making further progress in this exciting new
area. |
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