Origin and structures of solar eruptions Ⅱ： Magnetic modeling

• Published in: Science China. Earth sciences Vol. 60; no. 8; pp. 1408 - 1439
• Main Authors: Guo, Yang, Cheng, Xin, Ding, MingDe
• Format: Journal Article
• Language: English
• Published: Beijing Science China Press 01.08.2017; Springer Nature B.V
• Subjects: Atmospheric models; Boundary conditions; Components; Computational fluid dynamics; Coronal mass ejection; Dynamics; Earth and Environmental Science; Earth Sciences; Energy; Eruptions; Fields; Filaments; Finite volume method; Fluid flow; Flux; Helicity; Integration; Magnetic field; Magnetic fields; Magnetism; Magnetohydrodynamic models; Magnetohydrodynamics; Modelling; Photosphere; Polarized light; Preprocessing; Profiles; Projection; Prominences; Review; Sequencing; Solar activity regions; Solar atmosphere; Solar corona; Solar flares; Solar magnetic field; Structures; Three dimensional models; Topology; Velocity; 三维磁场; 太阳活动区; 太阳爆发; 拓扑结构; 流体动力学模型; 矢量磁场; 磁模型; 起源; Solar activity; Solar corona; Solar flares; Coronal Mass Ejections (CMEs); Magnetic fields; Solar photosphere
• ISSN: 1674-7313; 1869-1897
• DOI: 10.1007/s11430-017-9081-x

The topology and dynamics of the three-dimensional magnetic field in the solar atmosphere govern various solar eruptive phenomena and activities, such as flares, coronal mass ejections, and filaments/prominences. We have to observe and model the vector magnetic field to understand the structures and physical mechanisms of these solar activities. Vector magnetic fields on the photosphere are routinely observed via the polarized light, and inferred with the inversion of Stokes profiles. To analyze these vector magnetic fields, we need first to remove the 180° ambiguity of the transverse components and correct the projection effect. Then, the vector magnetic field can be served as the boundary conditions for a force-free field modeling after a proper preprocessing. The photospheric velocity field can also be derived from a time sequence of vector magnetic fields.Three-dimensional magnetic field could be derived and studied with theoretical force-free field models, numerical nonlinear force-free field models, magnetohydrostatic models, and magnetohydrodynamic models. Magnetic energy can be computed with three-dimensional magnetic field models or a time series of vector magnetic field. The magnetic topology is analyzed by pinpointing the positions of magnetic null points, bald patches, and quasi-separatrix layers. As a well conserved physical quantity,magnetic helicity can be computed with various methods, such as the finite volume method, discrete flux tube method, and helicity flux integration method. This quantity serves as a promising parameter characterizing the activity level of solar active regions.