Authors: Dana Longcope (Montana State University), Roger Scott (Montana State University)

A key element of the CSHKP eruptive flare model is a current sheet (CS) which, following its formation in the eruption, hosts the reconnection powering the flare. The most prevalent model for this field is a two-dimensional equilibrium with a straight, vertical CS terminating in a Y-type null. The strictly two-dimensional nature of this model hinders its detailed, quantitative application to actual flares. We present a method for extrapolating a magnetogram into a three-dimensional equilibrium containing CSs confined to one or more surfaces above a specified height. The field above this height is open and current-free except for equilibrium CSs whose locations and structure are determined along with the field. The upper field smoothly matches a completely potential lower field which itself matches the magnetogram at zero height. This new method is demonstrated by applying it to several well-studied eruptive flares. The results provide, for the first time, quantitative estimates of the structure of the CSs powering these flares, including a map of the field strength outside the CS and the surface current density within it.