Orientation and motion of a discontinuity from Cluster curlometer capability:: Minimum variance of current density -: art. no. L10804

A new technique to derive magnetopause key parameters such as orientation, velocity and thickness from multi-spacecraft observations is presented. The method is based on four-spacecraft determination of the current density, variance analysis to estimate the orientation and thereafter integration of the current density across the magnetopause to find the velocity. In cases where the spacecraft separation distance is small compared to the magnetopause thickness, the method can have advantages compared to other multi-spacecraft techniques. We show an application to Cluster data and compare the results with those from other multi-spacecraft methods as well as single-spacecraft methods such as minimum variance of the magnetic field combined with deHoff-mann-Teller analysis and the minimum Faraday residue method. Our results indicate that under favorable conditions, the use of Cluster as a curlometer can be very successful.