Resistive MHD reconstruction of two-dimensional coherent structures in space
| Autor: | Joachim Birn, Wai-Leong Teh, Bengt U. Ö. Sonnerup, Richard E. Denton |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2010 |
| Předmět: |
Ohm's law
Atmospheric Science Field (physics) Atmospheric-pressure plasma symbols.namesake Physics::Plasma Physics Electric field Earth and Planetary Sciences (miscellaneous) lcsh:Science Physics Resistive touchscreen lcsh:QC801-809 Geology Astronomy and Astrophysics Magnetic reconnection lcsh:QC1-999 Computational physics Magnetic field lcsh:Geophysics. Cosmic physics Classical mechanics Space and Planetary Science Physics::Space Physics symbols lcsh:Q Magnetohydrodynamics lcsh:Physics |
| Zdroj: | Annales Geophysicae, Vol 28, Pp 2113-2125 (2010) |
| ISSN: | 1432-0576 0992-7689 |
| Popis: | We present a reconstruction technique to solve the steady resistive MHD equations in two dimensions with initial inputs of field and plasma data from a single spacecraft as it passes through a coherent structure in space. At least two components of directly measured electric fields (the spacecraft spin-plane components) are required for the reconstruction, to produce two-dimensional (2-D) field and plasma maps of the cross section of the structure. For convenience, the resistivity tensor η is assumed diagonal in the reconstruction coordinates, which allows its values to be estimated from Ohm's law, E+v×B=η·j. In the present paper, all three components of the electric field are used. We benchmark our numerical code by use of an exact, axi-symmetric solution of the resistive MHD equations and then apply it to synthetic data from a 3-D, resistive, MHD numerical simulation of reconnection in the geomagnetic tail, in a phase of the event where time dependence and deviations from 2-D are both weak. The resistivity used in the simulation is time-independent and localized around the reconnection site in an ellipsoidal region. For the magnetic field, plasma density, and pressure, we find very good agreement between the reconstruction results and the simulation, but the electric field and plasma velocity are not predicted with the same high accuracy. |
| Databáze: | OpenAIRE |
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