LINEAR-MODELS OF STEADY-STATE, INCOMPRESSIBLE MAGNETIC RECONNECTION

The problem of linear, steady state reconnection in incompressible mag netic plasmas is addressed. A universal feature of all linear solution s is long current sheets contiguous with the equilibrium separatrices. Fast reconnection is associated with shear flow solutions that vary r apidly across the separatrices, over a scale length of order square-ro ot eta where eta is the dimensionless plasma resistivity. These findin gs are shown to be consistent with dynamic shear flow solutions associ ated with disturbances of current-free X-point equilibria in open-flow topologies. The development of length scales of order square-root eta is also a signature of fast dissipation for small amplitude, arbitrar ily compressible displacements in closed X-point equilibria. The impac t of these findings on conventional steady state reconnection models i s discussed.