HR: 0800h
AN: SM31B-0422    [Abstracts]
TI: A System Scale Theory for Fast Magnetic Reconnection
AU: * Knoll, D
EM: nol@lanl.gov
AF: Los Alamos National Laboratory, M.S. B216, Los Alamos, NM 87544 United States
AU: Chacon, L
EM: chacon@lanl.gov
AF: Los Alamos National Laboratory, M.S. B216, Los Alamos, NM 87544 United States
AU: Lapenta, G
EM: lapenta@lanl.gov
AF: Los Alamos National Laboratory, M.S. B216, Los Alamos, NM 87544 United States
AB: Magnetic reconnection is at the root of explosive phenomena such as solar flares, coronal mass ejections, plasmoid ejection from earth's magnetotail and major disruptions in magnetic fusion energy experiments. Plasmas in all the above mentioned cases are known to have negligible electric resistivity. This small resistivity can not explain the reconnection time scales observed in nature, when using the resistive MHD model. Recently much progress has been made considering the Hall MHD model. Hall physics has been shown to facility fast reconnection when the magnetic field shear scale length is in the order of the ion inertial length. However, in many systems of interest the initial scale lengths of the problem can not justify the use of Hall MHD. Thus a successful system scale theory must involve a current sheet thinning mechanism which brings the relevant scales down to the Hall scales. In this presentation we give examples of how naturally occurring hydrodynamic flows can provide such current sheet thinning [1,2,3] and where these occur in solar [4] and magnetosphere application [5]. We also discuss the primary obstacle for such flow to drive current sheet thinning, the build up of magnetic pressure, and how Hall MHD may overcome this obstacle. [1] Knoll and Brackbill, Phys. Plasmas, vol. 9, 2002 [2] Knoll and Chacon, PRL, vol. 88, 2002 [3] Knoll and Chacon, Phys. Plasmas, 2005 (submitted) [4] Lapenta and Knoll, ApJ, vol. 624, 2005 [5] Brackbill and Knoll, PRL, vol. 86, 2001
DE: 2723 Magnetic reconnection (7526, 7835)
DE: 7526 Magnetic reconnection (2723, 7835)
DE: 7835 Magnetic reconnection (2723, 7526)
SC: SPA-Magnetospheric Physics [SM]
MN: Fall Meeting 2005