HR: 1330h
AN: SH22A-0185    [PDF]
TI: Reconnection driven by natural flows in the solar corona
AU: Knoll, D
EM: nol@lanl.gov
AF: LANL, MS: K717, Los Alamos, nm 87545 United States
AU: * Lapenta, G
EM: lapenta@lanl.gov
AF: LANL, MS: K717, Los Alamos, nm 87545 United States
AB: Reconnection in the solar corona is believed to be important for a series of processes from flares and CMEs to coronal heating. However, theoretical understanding of the reconnection process still remains elusive. The reconnection rate predicted by the Sweet-Parker model is determined by resistivity and is very many orders of magnitude too small to explain the observations. A possible mechanism that can provide fast reconnection rate is driven reconnection, When flows drive field lines together, the rate of reconnection is determined by the driving mechanism and is independent of resistivity. In the present work we consider two possibilities: converging flows created by the long term evolution of coronal structures and converging flows due to flow instabilities. While the first mechanism has been invoked in the flux rope model of coronal mass ejections (CME) [1], the second mechanism has been proposed recently in studies of the evolution of helmet streamer configurations in presence of velocity shears [2]. Velocity shear induces the onset of the Kelvin Helmhotlz instability that leads to the compression of field lines in localized zones. Localized compression, in turn, leads to reconnection driven by the flow. The presence of the Kelvin-Helmholtz instability can be due to superAlfvenic field aligned flows or even to subAlfvenic flows across the field lines. [1] T.G. Forbes, J. Geophys. Res. 95, 11919 (1990). [2] G. Lapenta, D.A. Knoll, Solar Phys., 214, 107 (2003)
DE: 0644 Numerical methods
DE: 0654 Plasmas
DE: 7509 Corona
DE: 7511 Coronal holes
SC: SPA - Solar and Heliospheric Physics [SH]
MN: 2003 Fall Meeting