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Titel |
Phase space vortices in collisionless plasmas |
VerfasserIn |
P. Guio, S. Børve, L. K. S. Daldorff, J. P. Lynov, P. Michelsen, H. L. Pécseli, J. Rasmussen, K. Saeki, J. Trulsen |
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 ; 10, no. 1/2 ; Nr. 10, no. 1/2, S.75-86 |
Datensatznummer |
250007822
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Publikation (Nr.) |
copernicus.org/npg-10-75-2003.pdf |
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Zusammenfassung |
Results on the
formation and propagation of electron phase space vortices from laboratory
experiments are summarized. The electron phase space vortices were excited
in a strongly magnetized Q-machine plasma by applying a pulse to a segment
of a waveguide surrounding the plasma. Depending on the temporal variation
of the applied pulse, one or more phase space vortices can be excited, and
their interaction can be followed in space and time. We were able to
demonstrate, for instance, an irreversible coalescence of two such
vortices. These results are extended by numerical simulations, showing how
electron phase space vortices can also be formed by beam instabilities.
Furthermore, a study of ion phase space vortices is performed by numerical
simulations. Both codes allow for an externally applied magnetic field in
three spatial dimensions. Ion phase space vortices are formed by the
nonlinear saturation of the ion-ion two-stream instability, excited by
injecting an ion beam at the plasma boundary. By following the evolution
of the ion distribution of the velocity perpendicular to the direction of
propagation of the injected ion beam, we find a significant ion heating in
the direction perpendicular to the magnetic field associated with the ion
phase space vortices being formed. The results are relevant, for instance,
for the interpretation of observations by instrumented spacecraft in the
Earth's ionosphere and magnetosphere. |
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