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Session 56 - The Sun.
Oral session, Tuesday, January 14
Coronal mass ejections (CME) consist of huge eruptions of solar coronal plasma and magnetic field, and are now known to be the main drivers of geomagnetic disturbances. The energy source for CMEs must be magnetic since the plasma beta in the corona is observed to be low, and the gravitational energy can only increase as a result of eruption. Although there has been a great deal of work on coronal mass ejections in recent years, we argue that none of the previous models is able to satisfy the observational constraints, in particular, the result that the eruption begins at very low heights in the corona. For the case of the most energetic events which are usually accompanied by large eruptive flares, the magnetic field must blow open all the way down to the chromosphere. In this paper we propose a new model for CMEs. The key feature of our model is that magnetic reconnection occurs above the erupting flux, rather than below as in all previous models. We present theoretical arguments and numerical simulations demonstrating that our model can explain the observed opening of field lines down to the chromosphere.
This work was supported in part by NASA and ONR.
Program listing for Tuesday