Title: Cancellation, Prominence Formation, and Eruptions

Author_list: Welsch, B.T.

Abstract: Martin (1998) observed that the cancellation of photospheric
magnetic flux (see, e.g., Chae et al., 2004) is omnipresent during the
formation  of prominences.  In a series of MHD simulations of prominence
formation, Welsch et al.(in prep.) found that the magnetic reconnection
necessary to form prominences above the photosphere does not proceed
efficiently without flux cancellation, which accords with Martin's
observations.  To illuminate the significance of flux cancellation in
the formation of eruptive structures (if any), I report observed flux
cancellation rates around the time of eruptions from AR's 8210 and 8038.