MHD (Magnetohydrodynamic) Modeling of Energy Build-up Due to Photospheric Shearing Motion and Its Relation to Flare Prediction Criteria

摘要

An investigation of the evolution of active regions, leading to the buildup and storage of magnetic energy for eventual rapid release as the thermal, radiative and kinetic energy of solar flares is presented. This investigation is based on both observations and theoretical models. Solar observations utilized in the study were vector magnetograms, high-resolution hydrogen alpha filtergrams, flare data and sunspot pictures (for the energy buildup model). Parameters selected for the initial analysis, generally indicative of (available) magnetic energy buildup, include (1) the angle of shear, (2) the strength of the sheared field, (3) the longitudinal gradient (4) a parameter related to the shear volume, and in an observationally limited number of cases, (5) the data sample considered, significant flare production correlates well with indications of strong magnetic shear and energy storage. The theoretical models are based on magnetohydrodynamic theory. Specifically a two dimensional, non-planar, time-dependent MHD model was used to deduce the critical parameters as eventual input to a proposed shear/flare index . However, these theoretically deduced physical parameters have to date had only limited comparison with observations. This combined theoretical and observational study could lead to the development and refinement of a magnetic shear/flare index for the improvement of solar flare prediction technology. (jhd)