Magnetic energy release in flux pile-up merging

The problem of pressure limitations on the rate of flux pile-up magnetic re connection is studied. We first examine the recent suggestion of Jardine an d Allen (1998) for moderating the build-up of magnetic pressure in the curr ent sheet by considering inflows with nonzero vorticity. An analytic argume nt shows, however, that unbounded magnetic pressures in the limit of small resistivities can be avoided only at the cost of unphysical dynamic pressur es in the plasma. Hence, the pressure limitation on the reconnection rate i n a low-beta plasma cannot be avoided completely. Nevertheless, we demonstr ate that reconnection can be more rapid in a new solution that balances the build-up in dynamic pressure against both the plasma and magnetic pressure s. This exact MHD solution has the characteristics of merging driven by the coalescence instability. The maximum energy release rate of the model is c apable of explaining a modest solar flare.