HR: 08:15h
AN: SH51C-02    [Abstracts]
TI: Can we Improve the Preprocessing of Photospheric Vectormagnetograms by the Inclusion of Chromospheric Observations?
AU: * Wiegelmann, T
EM: wiegelmann@mps.mpg.de
AF: Max-Planck-Institute for Solar System Research, Max-Planck Str. 2, Katlenburg-Lindau, 37191, Germany
AU: Thalmann, J K
EM: thalmann@mps.mpg.de
AF: Max-Planck-Institute for Solar System Research, Max-Planck Str. 2, Katlenburg-Lindau, 37191, Germany
AU: Schrijver, C J
EM: schryver@lmsal.com
AF: Lockheed Martin Advanced Technology Center, Dept. ADBS. Bldg. 252, 3251 Hanover St., Palo Alto, CA 94304, United States
AU: DeRosa, M L
EM: derosa@lmsal.com
AF: Lockheed Martin Advanced Technology Center, Dept. ADBS. Bldg. 252, 3251 Hanover St., Palo Alto, CA 94304, United States
AU: Metcalf, T R
EM: metcalf@cora.nwra.com
AF: Northwest Research Associates, Colorado Research Associates Division, 3380 Mitchel Ln, Boulder, CO 90301, United States
AB: The solar magnetic field is key to understanding the physical processes in the solar atmosphere. Unfortunately, we can measure the magnetic field vector routinely with high accuracy only in the photosphere with, e.g., Hinode/SOT and in future with SDO/HMI. These measurements are extrapolated into the corona under the assumption that the field is force-free. That condition is not fulfilled in the photosphere, but is in the chromosphere and corona. In order to make the observed boundary data consistent with the force-free assumption, we therefore have to apply some transformations before nonlinear force-free extrapolation codes can be legitimately applied. We develop a minimization procedure that uses the measured photospheric field vectors as input to approximate a more chromospheric-like field. The procedure includes force-free consistency integrals, spatial smoothing, and - newly included in the version presented here - an improved match to the field direction as inferred from fibrils as can be observed in, e.g., chromospheric H-alpha images. We test the procedure using a model active-region field that included buoyancy forces at the photospheric level. We apply the combined preprocessing and nonlinear force-free extrapolation method to compute the coronal magnetic field in an active region measured with the Hinode/SOT instrument.
DE: 7500 SOLAR PHYSICS, ASTROPHYSICS, AND ASTRONOMY
DE: 7507 Chromosphere
DE: 7509 Corona
DE: 7524 Magnetic fields
DE: 7529 Photosphere
SC: SPA-Solar and Heliospheric Physics [SH]
MN: 2007 Fall Meeting