Reconstruction of time-varying reconnection rate and X-line location

Remote-sensing method developed on the basis of time-dependent Petschek-type reconnection model is applied to Cluster magnetotail measurements from 8 September 2002, where a series of earthward propagating NFTEs (nightside flux transfer events) was observed. The method utilizes single-spacecraft magnetic data as an input and provides the reconnection rate and the location of X-line as an output. For the first time the method is applied to a composite reconnection event consisting of three successive NFTEs following each other without any time delay. The reconnection distance is found to be between 27 and 30 R-E in the tail. The reconstructed electric field involves three 1-min scale pulses with total duration of similar to 4 min. The peak rates for individual pulses vary from 0.6 to 1.1 mV/m.