FORMATION, LEVITATION, AND STABILITY OF PROMINENCES IN THE MAGNETIZEDSOLAR ATMOSPHERE

We simulate the dynamic formation and ultimate stable support, against gravity, of a Kippenhahn-Schluter prominence at the apex of a magneti c arcade. As a preparatory step, we also elucidate the thermal structu re of the magnetized solar atmosphere, which consists of short, cool, chromospheric-like loops at low altitude and long, hot-apex, coronal l oops at high altitude. This investigation is completed in three steps: the creation of a background magnetothermal equilibrium, the initiati on and nonlinear formation of a massive siphon condensation with atten dant magnetic field deformation, and the verification of translational stability. This is all accomplished with a model based on the two-dim ensional magnetohydrodynamic equations, which also includes gravity, c ompressible flows, heating, radiation, anisotropic thermal conduction, and coupling to a deep chromosphere. The equilibrium solar atmosphere evolves to a complex structure even in the absence of a prominence. C ool and dense material fills the low-lying magnetic loops, producing a corrugated transition region between the hot and diffuse corona and t he chromosphere. Prominences subsequently form in response to a large isobaric enhancement of the density at the apex of a coronal loop. Mat erial siphons from the chromosphere as the result of a pressure depres sion driven by enhanced radiation, and forms a spatially localized, hi gh-density, low-temperature prominence. The gravitational force acting on the condensation mass distorts the local magnetic field, thereby p roducing a magnetic sling of normal polarity, which supports the promi nence. Prominences in simple arcades, for which the preprominence magn etic field has significant negative curvature at the apex, are found t o be unstable to a lateral displacement: they eventually fall down the magnetic field onto the chromosphere. In more complex arcades, in whi ch the initial magnetic field is nearly horizontal or has only small n egative curvature, prominences are both dynamically and thermally stab le.