TITLE:
Efficacy of Hilbert-Huang Transform (HHT) in the Analysis of Instantaneous Low Frequency Waves of Magnetosheath
AUTHORS:
Ekong U. Nathaniel, Nyakno J. George, Jewel I. Ibanga, Aniekan M. Ekanem
KEYWORDS:
Plasma Waves, Instantaneous Frequency, Empirical Mode Decomposition (EMD), Hilbert-Huang Transform (HHT)
JOURNAL NAME:
International Journal of Geosciences,
Vol.7 No.1,
January
13,
2016
ABSTRACT: The flow of supersonic
plasma is accompanied by a highly thermalized region called the Magnetoshealth
found after the bow shock. Enclosed within this region are different wave modes
associated with classes of boundaries which have been determined by different
methods. The efficacy of Hilbert-Huang transform (HHT) is based on the
conditionality of allowing for the local analysis of frequencies, which
presents the physical meaning of the original signal at that instant. The
observed data have been taken from Cluster II Fluxgate Magnetometer (FGM)
instrument that provides advantage for the analysis in three dimensions. The
result compares favourably with instantaneous frequencies computed using simple
Hilbert transform (SHT) with electric field measurements of Cluster II mission
already carried out in literatures. The result of this study has shown that HHT
provides the best applicability in the magnetosheath data analysis than the
wavelet and Fast Fourier Transform (FFT). The application of HHT based on its
advantages over other methods is viewed to be very critical in the analysis of
multi-frequency signals where different frequencies could be determined
distinctively at a point.