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Titel |
Debye-scale solitary structures measured in a beam-plasma laboratory experiment |
VerfasserIn |
B. Lefebvre, L.-J. Chen, W. Gekelman, P. Kintner, J. Pickett, P. Pribyl, S. Vincena |
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 ; 18, no. 1 ; Nr. 18, no. 1 (2011-01-25), S.41-47 |
Datensatznummer |
250013866
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Publikation (Nr.) |
copernicus.org/npg-18-41-2011.pdf |
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Zusammenfassung |
Solitary electrostatic pulses have been observed in numerous places of the
magnetosphere such as the vicinity of reconnection current sheets, shocks or
auroral current systems, and are often thought to be generated by energetic
electron beams. We present results of a series of experiments conducted at
the UCLA large plasma device (LAPD) where a suprathermal electron beam was
injected parallel to a static magnetic field. Micro-probes with tips smaller
than a Debye length enabled the detection of solitary pulses with positive
electric potential and half-widths 4–25 Debye lengths (λDe),
over a set of experiments with various beam energies, plasma densities and
magnetic field strengths. The shape, scales and amplitudes of the structures
are similar to those observed in space, and consistent with electron holes.
The dependance of these properties on the experimental parameters is shown.
The velocities of the solitary structures (1–3 background electron thermal
velocities) are found to be much lower than the beam velocities, suggesting
an excitation mechanism driven by parallel currents associated to the
electron beam. |
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