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| Titel |
Magnetic field generation in a jet-sheath plasma via the kinetic Kelvin-Helmholtz instability |
| VerfasserIn |
K.-I. Nishikawa, P. Hardee, B. Zhang, I. Duţan, M. Medvedev, E. J. Choi, K. W. Min, J. Niemiec, Y. Mizuno, A. Nordlund, J. T. Frederiksen, H. Sol, M. Pohl, D. H. Hartmann |
| 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 ; 31, no. 9 ; Nr. 31, no. 9 (2013-09-06), S.1535-1541 |
| Datensatznummer |
250086104
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| Publikation (Nr.) |
 copernicus.org/angeo-31-1535-2013.pdf |
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| Zusammenfassung |
| We have investigated the generation of magnetic fields associated with
velocity shear between an unmagnetized relativistic jet and an unmagnetized
sheath plasma. We have examined the strong magnetic fields generated by
kinetic shear (Kelvin–Helmholtz) instabilities. Compared to the previous
studies using counter-streaming performed by Alves et al. (2012), the
structure of the kinetic Kelvin–Helmholtz instability (KKHI) of our
jet-sheath configuration is slightly different, even for the global evolution
of the strong transverse magnetic field. In our simulations the major
components of growing modes are the electric field Ez, perpendicular to the flow boundary, and the magnetic
field By, transverse to the flow direction. After the By component is excited, an induced electric
field Ex, parallel to the flow direction, becomes significant. However, other field components remain
small. We find that the structure and growth rate of KKHI with mass ratios
mi/me = 1836 and mi/me = 20 are
similar. In our simulations saturation in the nonlinear stage is not as clear
as in counter-streaming cases. The growth rate for a mildly-relativistic jet
case (γj = 1.5) is larger than for a relativistic jet case
(γj = 15). |
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