HR: 17:50h
AN: SH34A-07 INVITED    [Abstracts]
TI: Intermittent Emission of High-Frequency Waves by Magnetic Reconnection Between Canopy Field and Small-Scale Horizontal Field
AU: * Isobe, H
EM: isobe@eps.s.u-tokyo.ac.jp
AF: Department of Earth and Planetary Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
AB: The energy source of coronal heating and solar wind acceleration is the interaction of magnetic field and thermal convection in the photosphere. Magnetoconvection has complicated bifurcation structure, and the mode, spectra and power of the waves generated in the photosphere depend on the nature of magnetoconvection in the photosphere. In order to study the relation between magnetoconvection and coronal heating/solar wind acceleration, we performed three-dimensional magnetohydrodynamic simulation of a domain that includes from upper convection zone to the corona. We first ran the simulation without magnetic field until convection developed to quasi-steady state, and then imposed a vertical and uniform magnetic field. We found that, in addition to the well-known fact that vertical magnetic field is swept into the downflow region, small scale horizontal fields as strong as 800G intermittently emerge in the photosphere. Even though the initial magnetic field is vertical and uniform, magnetic field in the convection zone become turbulent, and occasionally a bundle of strong magnetic flux is driven by the upward convection flow and emerges in the photosphere. Such horizontal fields undergo magnetic reconnection with pre-existing magnetic field in the chromosphere (so called "canopy" field), and then emit high-frequency (>0.05mHz) waves into the corona. We discuss the possible role of these processes in heating, acceleration and turbulence of the corona and the solar wind.
DE: 2149 MHD waves and turbulence (2752, 6050, 7836)
DE: 2169 Solar wind sources
DE: 7509 Corona
DE: 7526 Magnetic reconnection (2723, 7835)
DE: 7529 Photosphere
SC: SPA-Solar and Heliospheric Physics [SH]
MN: 2007 Fall Meeting