Modeling of prominence threads in magnetic fields:: Levitation by incompressible MHD waves

The nature of thin, highly inclined threads observed in quiescent prominences has puzzled solar physicists for a long time. When assuming that the threads represent truly inclined magnetic fields, the supporting mechanism of prominence plasma against gravity has remained an open issue. This paper examines the levitation of prominence plasma exerted by weakly damped MHD waves in nearly vertical magnetic flux tubes. It is shown that the wave damping, and resulting 'radiation pressure', caused predominantly by ion-neutral collisions in the 'cold' prominence plasma, may balance the acceleration of gravity provided the oscillation frequency is omega approximate to 2 rad s(-1) (f approximate to 0.5 Hz). Such short wave periods may be the result of small-scale magnetic reconnections in the highly fragmentary magnetic field of quiescent prominences. In the proposed model, the wave induced levitation acts predominantly on plasma - neutral gas mixtures.