Method for the determination of the height of a solar filament

Abstract

A comparison of the actual filament height above the solar photosphere with the limiting height calculated by magnetic data provides information about the filament stability margin and its readiness for eruption. A method is proposed for the determination of the height of solar filaments by a comparison of the position of the upper edge of the filament (spine) with the position of the polarity-inversion line of the potential magnetic field calculated for different heights. The line closest to the filament spine corresponds to its height. Observations of the Solar Terrestrial Relations Observatory (STEREO) spacecraft were used to verify the proposed method when they were at an angular distance of ~90° from the Earth and provided a side view of the filaments near the central meridian in observations from the Earth and near-Earth orbits. The proposed method can be useful in the estimation of the possible geoeffectiveness of filaments on the solar disk.