HR: 1340h
AN: SH44A-1721    [Abstracts]
TI: A First-Principles Analytical Theory for 2D Magnetic Reconnection in Electron and Hall Magnetohydrodynamics
AU: Chacon, L
EM: chacon@lanl.gov
AF: Los Alamos National Laboratory, PO Box 1663, Los Alamos, NM 87545, United States
AU: * Simakov, A N
EM: simakov@lanl.gov
AF: Los Alamos National Laboratory, PO Box 1663, Los Alamos, NM 87545, United States
AU: Zocco, A
EM: zocco_a@lanl.gov
AF: Los Alamos National Laboratory, PO Box 1663, Los Alamos, NM 87545, United States
AU: Zocco, A
EM: zocco_a@lanl.gov
AF: Burning Plasma Research Group, Dept. of Energetics, Politecnico di Torino, Corso Duca degli Abruzzi, 24, Torino, 10129, Italy
AB: Although the relevance of two-fluid effects in fast magnetic reconnection is well-known, (J. Birn et al., J. Geophys. Res., 106 (A3), 3715 (2001) a first-principles theory -- akin to Sweet and Parker's in resistive MHD -- has been elusive. Here, we present such a first principles steady-state analytical theory for electron MHD, (L. Chacón, A. N. Simakov, A. Zocco, Phys. Rev. Lett., submitted) and its extension to Hall MHD. (A. N. Simakov, L. Chacón, in preparation) The theory discretizes the extended MHD equations at the reconnection site, leading to a set of time-dependent ODEs. Their steady-state analysis, which describes the system at or around the point of maximum reconnection rate, provides predictions for the scaling of relevant quantities with the dissipation coefficients (e.g, resistivity and hyper-resistivity) and other relevant parameters. In particular, we will show that EMHD admits both elongated and open-X point configurations of the reconnection region, and that the reconnection rate can be shown not to scale explicitly with the dissipation parameters. This result is, to our knowledge, the first analytical confirmation of the possibility of fast magnetic reconnection in EMHD. In Hall MHD, the transition between resistive MHD and EMHD is studied, and scalings with the ion inertial length are obtained.
DE: 7526 Magnetic reconnection (2723, 7835)
SC: SPA-Solar and Heliospheric Physics [SH]
MN: 2007 Fall Meeting