Author:

Keywords:

mhd, sun : corona, sun : magnetic fields, sun : prominences, large-scale corona, force-free field, quiescent prominences, mass ejections, flux ropes, magnetostatic structures, driven evolution, mhd equilibria, model, line, Science & Technology, Physical Sciences, Astronomy & Astrophysics, MHD, Sun : corona, Sun : magnetic fields, Sun : prominences, LARGE-SCALE CORONA, FORCE-FREE FIELD, QUIESCENT PROMINENCES, MASS EJECTIONS, FLUX ROPES, MAGNETOSTATIC STRUCTURES, DRIVEN EVOLUTION, MHD EQUILIBRIA, MODEL, LINE, astro-ph, 0201 Astronomical and Space Sciences, 0202 Atomic, Molecular, Nuclear, Particle and Plasma Physics, 0306 Physical Chemistry (incl. Structural), 5101 Astronomical sciences, 5107 Particle and high energy physics, 5109 Space sciences

Abstract:

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