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C. R. DeVore, S. K. Antiochos (NRL)
The structure and stability of the magnetic field play critical roles in the formation, evolution, and eventual eruption of solar prominences. We have shown previously that a three-dimensional coronal arcade with strong localized shear exhibits several characteristic properties measured or inferred from prominence observations. These include alignment with the polarity inversion line of the photospheric field, inverse magnetic polarity in the body of the prominence, the necessary restraining overlying arcade field, formation of helical fields at high shear, and linkage of formerly distinct prominences where they come into contact and their magnetic fields reconnect. Our studies also suggested that the resulting structures are very stable, showing no tendency to erupt violently as solar prominences frequently do.
We now are extending these investigations by including in the model the corona’s expanding spherical geometry and its gravitationally stratified mass density and thermal pressure. Our expectation is that topologically bipolar prominence structures will be found to rise to greater heights than in our previous cartesian studies, but still will be unable to attain the free energy needed to open the field. A multipolar structure in a breakout configuration, on the other hand, in principle could approach its free-energy threshold and then erupt once the breakout reconnection commences. This outcome would be qualitatively different from our prior results. Progress on these fronts and the implications for our understanding of prominences will be reported.
This research was supported by NASA and ONR.
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Bulletin of the American Astronomical Society, 36 #2
© YEAR. The American Astronomical Soceity.