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Session 8 - Corona III.
Oral session, Saturday, June 28
Ballroom A, Chair: Barry LaBonte

[8.04] Role of the Streamer Cavity in CME Energetics

R. Wolfson, S. Saran (Middlebury College)

Magnetic energy is commonly believed to power coronal mass ejections (CMEs). Theory and numerical experiments show that the energy stored in force-free magnetic fields is sufficient only to open the coronal magnetic field, but not to accelerate the mass ejection nor to lift it against solar gravity. Simple models involving non-force free cross-field currents can store more magnetic energy, but in the process they develop large negative gravitational energies, giving negative total energy.

We have developed a coronal model that incorporates a more realistic density profile, similar to that of the coronal helmet streamers in which most CMEs originate. In this model, the presence of the underdense streamer cavity permits the growth of magnetic energy without as much negative gravitational energy. We thus achieve pre-CME coronal states with positive total energy. In some cases the positive energy is a mix of magnetic and gravitational energy; in other cases magnetic energy dominates. We conclude in the latter cases that magnetic energy is sufficient to power mass ejections in our model corona.

Program listing for Saturday