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| Titel |
Magnetic field amplification in electron phase-space holes and related effects |
| VerfasserIn |
R. A. Treumann, W. Baumjohann |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
0992-7689
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| Digitales Dokument |
URL |
| Erschienen |
In: Annales Geophysicae ; 30, no. 4 ; Nr. 30, no. 4 (2012-04-19), S.711-724 |
| Datensatznummer |
250017215
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| Publikation (Nr.) |
 copernicus.org/angeo-30-711-2012.pdf |
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| Zusammenfassung |
| Three-dimensional electron phase-space holes are shown to have positive charges
on the plasma background, which produce a radial electric field and force the
trapped electron component into an azimuthal drift. In this way electron
holes generate magnetic fields in the hole. We solve the cylindrical hole
model exactly for the hole charge, electric potential and magnetic field. In
electron holes, the magnetic field is amplified on the flux tube of the hole;
equivalently, in ion holes the field would be decreased. The flux tube
adjacent to the electron hole is magnetically depleted by the external hole
dipole field. This causes magnetic filamentation. It is also shown that holes
are massive objects, each carrying a finite magnetic moment. Binary magnetic
dipole interaction of these moments will cause alignment of the holes into
chains along the magnetic field or, in the three-dimensional case, produce a
magnetic fabric in the volume of hole formation. Since holes, in addition to
being carriers of charges and magnetic moments, also have finite masses, they
behave like quasi-particles, performing E × B, magnetic field, and
diamagnetic drifts. In an inhomogeneous magnetic field, their magnetic
moments experience torque, which causes nutation of the hole around the
direction of the magnetic field, presumably giving rise to low frequency
magnetic modulations like pulsations. A gas of many such holes may allow for
a kinetic description, in which holes undergo binary dipole interactions. This
resembles the polymeric behaviour. Both magnetic field generation and
magnetic structure formation are of interest in auroral, solar coronal and
shock physics, in particular in the problem of magnetic field filamentation
in relativistic foreshocks and cosmic ray acceleration. |
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