Journal cover Journal topic
Annales Geophysicae An open-access journal of the European Geosciences Union
Ann. Geophys., 31, 1611-1617, 2013
© Author(s) 2013. This work is distributed under
the Creative Commons Attribution 3.0 License.
Regular paper
27 Sep 2013
Determination of wave vectors using the phase differencing method
S. N. Walker1 and I. Moiseenko2 1Department of Automatic Control and Systems Engineering, University of Sheffield, Sheffield, UK
2Space Research Institute of the Russian Academy of Sciences, Moscow, Russia
Abstract. Due to the collisionless nature of space plasmas, plasma waves play an important role in the redistribution of energy between the various particle populations in many regions of geospace. In order to fully comprehend such mechanisms it is necessary to characterise the nature of the waves present. This involves the determination of properties such as wave vector k. There are a number of methods used to calculate k based on the multipoint measurements that are now available. These methods rely on the fact that the same wave packet is simultaneously observed at two or more locations whose separation is small in comparison to the correlation length of the wave packet. This limitation restricts the analysis to low frequency (MHD) waves. In this paper we propose an extension to the phase differencing method to enable the correlation of measurements that were not made simultaneously but differ temporally by a number of wave periods. The method is illustrated using measurements of magnetosonic waves from the Cluster STAFF search coil magnetometer. It is shown that it is possible to identify wave packets whose coherence length is much less than the separation between the measurement locations. The resulting dispersion is found to agree with theoretical results.

Citation: Walker, S. N. and Moiseenko, I.: Determination of wave vectors using the phase differencing method, Ann. Geophys., 31, 1611-1617,, 2013.
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