Models of Structure and Dynamics of Prominences

Abstract

The discussion in Working Group1was centered around 3 theoretical models. The participants were well aware of the fact that these idealized models have only limited value towards our goal of understanding the complex physical phenomena of quiescent prominences. We used these models mainly as a common basis for our discussion. The models, shown in Figure 1 are all 2-dimensional and only cross-sections normal to the long axis of the prominence are drawn. They are based on different magnetic field configurations. In all 3 models currents flow inside the prominence giving rise to a Lorentz-force which keeps the material from falling freely towards the surface of the Sun. Due to horizontal motion parallel to the prominence of the foot points of opposite polarity a magnetic field normal to the plane drawn will be induced. This then implies additional currents in the corona surrounding the prominence. Note that those field lines in the Kuperus and Raadu model which are open cannot maintain any shear and therefore must lie in the plane. The circular lines in the model of Malville result from a projection of helical field structures.