Abstract

Working toward a physical understanding of how solar wind/magnetosphere coupling works, four arguments are presented indicating that the solar wind electric field vsw × Bsw does not control the rate of reconnection between the solar wind and the magnetosphere. Those four arguments are (1) that the derived rate of dayside reconnection is not equal to solar wind electric field, (2) that electric field driver functions can be improved by a simple modification that disallows their interpretation as the solar wind electric field, (3) that the electric field in the magnetosheath is not equal to the electric field in the solar wind, and (4) that the magnetosphere can mass load and reduce the dayside reconnection rate without regard for the solar wind electric field. The data are more consistent with a coupling function based on local control of the reconnection rate than the Axford conjecture that reconnection is controlled by boundary conditions irrespective of local parameters. Physical arguments that the solar wind electric field controls dayside reconnection are absent; it is speculated that it is a coincidence that the electric field does so well at correlations with geomagnetic indices.