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| Titel |
"Thick" equilibrium current sheets in the Earth’s magnetotail: influence of guiding field. Comparison with experimental data. |
| VerfasserIn |
L. Zelenyi, H. Malova, V. Popov, A. Artemiev, A. Petrukovich, D. Delcourt |
| Konferenz |
EGU General Assembly 2009
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250027526
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| Zusammenfassung |
| The self-consistent theory of “thick” current sheets in collisionless plasma with
double-temperature distribution or high-temperature tail is developed taking into account the
interaction of several plasma components: electrons, cold and hot ions. The quasi-adiabatic
approximation is used to describe the motion of ions, whereas the fluid approximation is
taken as a more appropriate one for electrons. Grad-Shafranov equations are solved to obtain
the equilibrium structure of current sheet. It is shown that self-consistent equilibrium
solutions might exist in a wide range of parameters of the system. The corresponding profiles
of current densities and magnetic fields depend on the relative plasma density of colder and
warmer ion populations and their temperatures. These solutions might describe single as well
as several-peaked current sheets. The thicknesses of the obtained current equilibria are
several times larger than the characteristic Larmor radius (as in the models with a
single plasma component). Therefore theory provides possible explanation of the
appearance of a really thick (-¥ Larmor radii) current sheets often observed in space
experiments. We also studied the influence of a guiding magnetic field on such
equilibrium. It is found that the presence of guiding field might substantially change
properties of charged particle trajectories, which significantly modify the current
sheet structure. This work demonstrates that characteristic profiles of current sheet
parameters provided by our model are in good agreement with the ones observed
experimentally.
This work was supported by RFBR grants 08-02-00407, 06-02-72561 and Russian
Ministry of Science program (HIII-472.2008.2) |
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