A Surge Erupts

AR11176 hosted a major (but unseen) flare while rounding the sun's eastern limb. As well as the post-flare loops logged (see below) many surges emerged from the active region's spots. The image shows a presumed surge that emerged near the preceding (p) spot. Though cloud intervened, the surge was seen to reach a peak height ~110Mm with average velocity ~110 Km/s, before recoiling.  The (p) spot hosted many very large surges days later, around Mar 23, as it crossed the disc. (This sketch omits all other detail in the AR for clarity. The post flare loops and other surges shown in the log below were all active during this surge)

Surges Zirin tell us (Astrophysics of the Sun, 1986) are collimated ejecta - as in a "gun barrel", suggesting (p389) they are due to "conversion of all the internal energy of a small flare into kinetic energy via a magnetic nozzle".  But how do we explain their recoil back into the sun? No more recent modelling of surges has so far been located - though it may have been published (Any citations?)