caa a22 4500 445346582 CHVBK 20180317142830.0 cr unu---uuuuu 170323e20110301xx s 000 0 eng 10.1007/s11207-010-9691-4 doi (NATIONALLICENCE)springer-10.1007/s11207-010-9691-4 Study on Two Methods for Nonlinear Force-Free Extrapolation Based on Semi-Analytical Field [Elektronische Daten] [S. Liu, H. Zhang, J. Su, M. Song] In this paper, two semi-analytical solutions of force-free fields (Low and Lou, Astrophys. J. 352, 343, 1990) have been used to test two nonlinear force-free extrapolation methods. One is the boundary integral equation (BIE) method developed by Yan and Sakurai (Solar Phys. 195, 89, 2000), and the other is the approximate vertical integration (AVI) method developed by Song et al. (Astrophys. J. 649, 1084, 2006). Some improvements have been made to the AVI method to avoid the singular points in the process of calculation. It is found that the correlation coefficients between the first semi-analytical field and extrapolated field using the BIE method, and also that obtained by the improved AVI method, are greater than 90% below a height 10 of the 64×64 lower boundary. For the second semi-analytical field, these correlation coefficients are greater than 80% below the same relative height. Although differences between the semi-analytical solutions and the extrapolated fields exist for both the BIE and AVI methods, these two methods can give reliable results for heights of about 15% of the extent of the lower boundary. Springer Science+Business Media B.V., 2010 Active regions nationallicence Magnetic fields nationallicence Photosphere nationallicence Liu S. Key Laboratory of Solar Activity, National Astronomical Observatory, Chinese Academy of Sciences, Beijing, China aut Zhang H. Key Laboratory of Solar Activity, National Astronomical Observatory, Chinese Academy of Sciences, Beijing, China aut Su J. Key Laboratory of Solar Activity, National Astronomical Observatory, Chinese Academy of Sciences, Beijing, China aut Song M. Purple Mountain Observatory, Chinese Academy of Sciences, 2 West Beijing Road, Nanjing, China aut Solar Physics Springer Netherlands 269/1(2011-03-01), 41-57 0038-0938 269:1<41 2011 269 11207 https://doi.org/10.1007/s11207-010-9691-4 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s11207-010-9691-4 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Liu S. Key Laboratory of Solar Activity, National Astronomical Observatory, Chinese Academy of Sciences, Beijing, China aut NATIONALLICENCE 700 1- Zhang H. Key Laboratory of Solar Activity, National Astronomical Observatory, Chinese Academy of Sciences, Beijing, China aut NATIONALLICENCE 700 1- Su J. Key Laboratory of Solar Activity, National Astronomical Observatory, Chinese Academy of Sciences, Beijing, China aut NATIONALLICENCE 700 1- Song M. Purple Mountain Observatory, Chinese Academy of Sciences, 2 West Beijing Road, Nanjing, China aut NATIONALLICENCE 773 0- Solar Physics Springer Netherlands 269/1(2011-03-01), 41-57 0038-0938 269:1<41 2011 269 11207 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer