34th Solar Physics Division Meeting, June 2003
Session 5 Coronal Mass Ejections I
Poster, Monday, June 16, 2003, 3:30-5:00pm, Mezzanine

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[5.14] A Flux-Rope Model of CME Rim-Cavity Density Structure

J. Krall, J. Chen (Plasma Physics Division, Naval Research Laboratory)

A density model is developed for a coronal flux rope with a specified magnetic field configuration. We find that the flux-rope plasma density is enhanced off axis, where the magnetic field lines are least twisted. This occurs as a result of the flow of plasma from the foot points to the apex of the flux rope. The center-to-edge density enhancement is sensitive to the current profile within the flux rope, with a more highly-peaked channel resulting in a greater center-to-edge density enhancement. Assuming self-similar expansion of the flux rope cross section from foot points (flux rope radius af) to the corona (radius a), the maximum possible density enhancement is \rho(r=a)/\rho(r=0) ~q a/af. Assuming that a flux-rope coronal mass ejection (CME) results from the eruption of a coronal flux rope, the CME density, neglecting the prominence, is obtained. The resulting model CME is tested against the data by computing synthetic coronagraph images. Thus, the observed rim-cavity morphology of CMEs is explained.

Work supported by ONR and NASA

The author(s) of this abstract have provided an email address for comments about the abstract: krall@ppdmail.nrl.navy.mil

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