ACHIEVING SELF-CONSISTENT NONLINEAR FORCE-FREE MODELING OF SOLAR ACTIVE REGIONS

A self-consistent nonlinear force-free solution for a solar active region magnetic field

Nonlinear force-free solutions for the magnetic field in the solar corona constructed using photospheric vector magnetic field boundary data suffer from a basic problem: the observed boundary data are inconsistent with the nonlinear force-free model. Specifically, there are two possible choices of boundary conditions on vertical current provided by the data, and the two choices lead to differen...

Consistent determination of quasi force-free magnetic fields from observations in solar active regions

The classical concept of extrapolating the photospheric magnetic field from line-of-sight measurements B` assuming a pure force-free field is revisited and a new procedure is proposed which is based on: 1) non-vanishing magnetic forces, 2) known horizontal forces from direct measurement of pressure or a related quantity (continuum brightness), 3) a small perturbation to the potential or linear ...

An ambiguity-free determination of JZ in solar active regions

We propose a way to derive a radial electric current density from vector magnetograms that is free of any particular choice of the two possible azimuths for the plane of the sky field. The method is applied to active region data obtained with the Advanced Stokes Polarimeter (ASP). A comparison of this current density with that derived for two particular sets of possible azimuth assignments allo...

Reconstruction of Nonlinear Force-free Fields and Solar Flare Prediction

A brief review is presented of methods for calculating nonlinear force-free fields, with emphasis on a new, fast current-field iteration procedure. The motivation is to reconstruct coronal magnetic fields using high resolution vector magnetic field boundary data from a new generation of spectro-polarimetric instruments. Methods of solar flare prediction are also reviewed, with focus on the need...

Reconstruction of Solar Coronal Linear Force-Free Magnetic Field