MODE RECOGNITION OF MHD WAVE-FIELDS AT INCOMPLETE DISPERSION MEASUREMENTS

A recognition formalism is presented for searching for and identifying the modes in a magnetohydrodynamic wave field. The method provides th e contributions of the wave energy in the different modes for one prop agation direction. Forward and backward running waves are also disting uished. The method developed is also applicable when the frequency and wave number of a wave field are not known simultaneously or when the dispersion of different modes is degenerate. The wave field is analyse d with respect to its generalised polarisation of the state vec tor. T he applicability of the method is tested using simulated data and real data from the-experiments onboard the Giotto spacecraft near comet P/ Halley. In both cases unique identification Of the different wave mode s is achieved.