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NAM2012 - All Presentation Details

Record 623 of 756

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Comparing force-free reconstructions of the solar corona based on SDO/HMI and SOLIS/VSM magnetograms

Author: Julia Thalmann

Max Planck Institute for Solar System Research

Co-Authors: A. Pietarila (National Solar Observatory, 950 N. Cherry Avenue, Tucson, AZ 85719, USA); X. Sun (W. W. Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA 94305, USA); T. Wiegelmann (Max Planck Institute for Solar System Research, Max-Planck-Str. 2, 37191 Katlenburg-Lindau, Germany)

Session: SP2: Solar coronal magnetic fields

Presentation type: Talk      10:27  Friday 30th 10:00-11:15 


The magnetic structure of the solar corona, in which presently no estimations of the magnetic field vector are routinely performed, is a viable field of research. To overcome the nonavailability of routine coronal magnetic field recordings, one makes use of the phtospheric magnetic field vector which is obtained from measurements of Stokes profiles on a regular basis. Based on the photospheric field as an input, force-free field approaches are used to estimate the magnetic field configuration in the higher atmospheric layers where magnetic forces are assumed to dominate. For the success of such force-free extrapolations it is necessary to preprocess the retrieved photospheric magnetic field vector in order to achieve suitable lower boundary conditions. Moreover, measurement uncertainties, as caused by noise or the particular inversion and azimuth ambiguity removal techniques, have to be taken into account. We use SDO/HMI and SOLIS/VSM photospheric magnetic field measureme! nts to model the force-free coronal field above solar active regions. Beside searching for the optimum modelling parameters for the particular instruments we compare the total magnetic energy content and free magnetic energy of the coronal model volumes and relate the appearing distinctions to the photospheric quantities such as the magnetic fluxes and electric currents.

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