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We compute the change in the Lorentz force integrated over the outer solaratmosphere implied by observed changes in vector magnetograms that occur duringlarge, eruptive solar flares. This force perturbation should be balanced by anequal and opposite force perturbation acting on the solar photosphere and solarinterior. The resulting expression for the estimated force change in the solarinterior generalizes the earlier expression presented by Hudson, Fisher andWelsch (CS-383, ASP, 221, 2008), providing horizontal as well as vertical forcecomponents, and provides a more accurate result for the vertical component ofthe perturbed force. We show that magnetic eruptions should result in themagnetic field at the photosphere becoming more horizontal, and hence shouldresult in a downward (towards the solar interior) force change acting on thephotosphere and solar interior, as recently argued from an analysis ofmagnetogram data by Wang and Liu (Astrophys. J. Lett. 716, L195, 2010). Wesuggest the existence of an observational relationship between the force changecomputed from changes in the vector magnetograms, the outward momentum carriedby the ejecta from the flare, and the properties of the helioseismicdisturbance driven by the downward force change. We use the impulse driven bythe Lorentz-force change in the outer solar atmosphere to derive an upper limitto the mass of erupting plasma that can escape from the Sun. Finally, wecompare the expected Lorentz-force change at the photosphere with simpleestimates from flare-driven gasdynamic disturbances and from an estimate of theperturbed pressure from radiative backwarming of the photosphere in flaringconditions.

Global Forces in Eruptive Solar Flares: The Lorentz force Acting on the Solar Atmosphere and the Solar Interior