A phenomenological, kinematical model of the coronal magnetic fields in terms of thin flux tubes rising from the photosphere

Abstract

A kinematical model is necessary for understanding the gross structure of the coronal magnetic field and its slow evolution in consistency with the small scale structure of the photospheric fields. Here we have developed a preliminary phenomenological model in terms of flux tubes of flux amounts ≈ 1017 − 1018.5 Mx rising across the inner corona in the form of arches and opening out in the outer corona. In contrast to Parker’s estimate, this model is consistent with the observed spans of the chromospheric fibrils and x-ray arches. It is also consistent with the number of flux tubes present above the photosphere as estimated from the observed abundance of spicules.