A 2-D MODEL FOR THE SUPPORT OF A POLAR-CROWN SOLAR PROMINENCE

We present a 2-D potential-field model for the magnetic structure in t he environment of a typical quiescent polar-crown prominence. The fiel d is computed using the general method of Titov (1992) in which a curv ed current sheet, representing the prominence, is supported in equilib rium by upwardly directed Lorentz forces to balance the prominence wei ght. The mass density of the prominence sheet is computed in this solu tion using a simple force balance and observed values of the photosphe ric and prominence magnetic field. This calculation gives a mass densi ty of the correct order of magnitude. The prominence sheet is surround ed by an inverse-polarity held configuration adjacent to a region of v ertical, open polar field in agreement with observations. A perturbati on analysis provides a method for studying the evolution of the curren t sheet as the parameters of the system are varied together with an ex amination of the splitting of an X-type neutral point into a current s heet.