Abstract
The earth's foreshock is a region where particularly large amplitude MHD waves are commonly observed. They exhibit various waveforms, suggesting that nonlinear interaction between the waves is in progress. In a previous paper (Hada et al., 2003) we have introduced a method to quantitatively evaluate the strength of phase coherence among the waves from a given time series data. Here we further develop our method by applying wavelet filtering technique. From the analysis it was found that, although the turbulence is consisted of waves with a wide range of plasma rest frame frequencies, only those frequencies lower than the ion gyrofrequency are responsible for generating the phase coherence.
Similar content being viewed by others
References
Hada, T., Koga, D. and Yamamoto, E.: 2003, ‘Phase Coherence of MHD Waves in the Solar Wind’, Space Sci.Rev. this issue.
Farge, M.: 1992, ‘Wavelet Transforms and Their Application to Turbulence’, Ann.Rev.Fluid Mech. 24, 395.
Torrence, C. and Compo, G. P.: 1998, ‘A Practical Guide to Wavelet Analysis’, Bull.Amer.Meteor.Soc. 79, 61.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Koga, D., Hada, T. Phase coherence of foreshock MHD waves: wavelet analysis. Space Science Reviews 107, 495–498 (2003). https://doi.org/10.1023/A:1025510225311
Issue Date:
DOI: https://doi.org/10.1023/A:1025510225311