Magnetohydrostatic Solar Prominences in Near‐Potential Coronal Magnetic Fields

Abstract

We present numerical magnetohydrostatic solutions describing the\ngravitationally stratified, bulk equilibrium of cool, dense prominence plasma\nembedded in a near-potential coronal field. These solutions are calculated\nusing the FINESSE magnetohydrodynamics equilibrium solver and describe the\nmorphologies of magnetic field distributions in and around prominences and the\ncool prominence plasma that these fields support. The equilibrium condition for\nthis class of problem is usually different in distinct subdomains, separated by\nfree boundaries, across which solutions are matched by suitable continuity or\njump conditions describing force balance. We employ our precise finite element\nelliptic solver to calculate solutions not accessible by previous analytical\ntechniques with temperature or entropy prescribed as free functions of the\nmagnetic flux function, including a range of values of the polytropic index,\ntemperature variations mainly across magnetic field lines and photospheric\nfield profiles sheared close to the polarity inversion line. Out of the many\nexamples computed here, perhaps the most noteworthy is one which reproduces\nprecisely the three-part structure often encountered in observations: a cool\ndense prominence within a cavity/flux rope embedded in a hot corona. The\nstability properties of these new equilibria, which may be relevant to solar\neruptions, can be determined in the form of a full resistive MHD spectrum using\na companion hyperbolic stability solver.\n