MAGNETIC-CONFIGURATION OF CORONAL STREAMERS AND THREADS

We give a short account of the most prominent structures of the interm ediate corona. Then we propose an axially symmetrical model for corona l streamers, according to which charged particles move along magnetic surfaces whose sources are electrical currents situated in the vicinit y of the photosphere. The simplest current configuration is a pair of coaxial, coplanar, circular, and oppositely directed currents parallel to the photosphere. Magnetic surfaces for this current distribution e xhibit a helmet-shaped separatrix and a saddle point. The temperature profile along the streamer can be predicted qualitatively if one takes into account the conservation of an adiabatic invariant in the drift theory of the charged particle motion.