Flow-through magnetic reconnection -: art. no. 1626

[1] This note reports properties of a little-studied but possibly common mode of magnetic reconnection-flow-through reconnection'' or FTR''-characterized by plasma flowing at high speed right through a stationary reconnection site. FTR is readily identified in global MHD simulations by the following diagnostic properties, which affect slab-like portions (tongues) of the magnetopause, usually at high latitudes and along the flanks. 1. A magnetic null point lies near the downwind extreme of an FTR tongue. 2. Elsewhere within the tongue the magnetic field is also weak. 3. Electric current density is strong. 4. J-dot-E'' dissipation is strong. 5. Most remarkable, the electric field is antiparallel to and stronger than -V x B, the motional electric field. This last property implies that plasma and magnetic field flow in opposite directions-plasma downwind, magnetic field upwind. Here we discuss FTR for strictly northward interplanetary magnetic field, which manifests FTR properties in idealized geometry.