Holly R. Gilbert, Thomas E. Holzer, Joan T. Burkepile, and Arthur J. Hundhausen, "Active and Eruptive Prominences and Their Relationship to Coronal Mass Ejections", ApJ 537, 503 (2000) (ADS link)
Click on the image above for a larger version of the .gif, or get the .ps.gz file (420 kB).
This cartoon shows a clear explanation for the separation of erupting filaments (the "partial eruption" of F. Tang?) on the basis of the field polarity - see the paper for a clear description of normal and inverse polarity models.
Jan. 10, 2007