Computing Nonlinear Force-Free Coronal Magnetic Fields in Spherical Geometry

Reconstruction of Solar Coronal Linear Force-Free Magnetic Field

reconstruction of solar coronal linear force-free magnetic field

Relationship between photospheric currents and coronal magnetic helicity for force-free bipolar fields

Aims. The origin and evolution of the magnetic helicity in the solar corona are not well understood. For instance, the magnetic helicity of an active region is often about 1042 Mx2 (1026 Wb2), but the observed processes whereby it is thought to be injected into the corona do not yet provide an accurate estimate of the resulting magnetic helicity budget or time evolution. The variation in magnet...

Calculating and Testing Nonlinear Force-Free Fields

Improvements to an existing method for calculating nonlinear force-free magnetic fields (Wheatland 2006, Solar Phys. 238, 29) are described. In particular a solution of the 3-D Poisson equation using 2-D Fourier transforms is presented. The improved nonlinear force-free method is demonstrated in application to linear force-free test cases with localized non-zero values of the normal component o...

Nonlinear force-free coronal magnetic field modeling scheme based on the direct boundary integral formulation

The boundary integral equation (BIE) method was first proposed by Yan and Sakurai [2000], which is used to extrapolate the nonlinear force-free magnetic field in the solar atmosphere. Recently, Yan and Li [2006] improved the BIE method and proposed the direct boundary integral equation (DBIE) formulation, which represents the nonlinear force-free magnetic field by direct integration of the magn...