Articles | Volume 26, issue 11
https://doi.org/10.5194/angeo-26-3389-2008
https://doi.org/10.5194/angeo-26-3389-2008
24 Oct 2008
 | 24 Oct 2008

Evaluation of bispectrum in the wave number domain based on multi-point measurements

Y. Narita, K.-H. Glassmeier, P. M. E. Décréau, T. Hada, U. Motschmann, and Y. Nariyuki

Abstract. We present an estimator of the bispectrum, a measure of three-wave couplings. It is evaluated directly in the wave number domain using a limited number of detectors. The ability of the bispectrum estimator is examined numerically and then it is applied to fluctuations of magnetic field and electron density in the terrestrial foreshock region observed by the four Cluster spacecraft, which indicates the presence of a three-wave coupling in space plasma.